By Sajad, Co-founder at cellbot — 25 years in the tech repair industry

Published: 23 September 2025 · Editorially reviewed: 26 August 2026

Evidence basis: UK repair-shop stock-control method; current GOV.UK, Environment Agency and HSE guidance; all reorder examples are illustrative and must be replaced with the shop's observed demand and supplier lead time.

Repair shop inventory management is the control of each part from purchase to one of four outcomes: fitted to a job, returned to the supplier, retained as usable stock or recorded as damaged or waste. The system works when the physical quantity, stock record, job record and accounts can be reconciled without guesswork.

The goal is not to hold every possible part. It is to keep reliable stock for predictable demand while ordering the long tail against an approved job.

!Repair-shop inventory control loop from part identity and receipt through reservation and fitting to count, return or waste evidence

Give every part an unambiguous identity

A useful stock record needs more than “iPhone screen”. Include:

  • internal SKU;
  • manufacturer, device family and exact model or variant;
  • part type and colour where relevant;
  • supplier's part number;
  • quality or source tier using a defined vocabulary;
  • compatibility and calibration notes;
  • landed unit cost;
  • storage location;
  • quantity available, reserved, quarantined and on order; and
  • serial, batch or lot reference when the part or risk justifies it.

Do not rely on the supplier title remaining unchanged. Your internal SKU should remain stable even if a supplier changes its catalogue description.

Use barcode labels where they save time, but do not add a scanning project before locations and statuses are disciplined. A clearly labelled bin and one required job-allocation step solve most early errors.

Download the repair-shop inventory control register. It includes part identity, demand, lead time, safety stock, reorder point, availability, receipt, batch, count and decision fields. The sample rows are fictional and the formulas should be checked against the shop's own rules.

Separate stock by demand and consequence

ABC classification ranks items by annual usage value: quantity used multiplied by unit cost. A items consume the most cash and deserve tight review; C items consume less. Add a second view for demand consistency or operational consequence.

A low-cost adhesive may be financially minor but can stop a common repair. A high-cost display may be used rarely and should be ordered to a job. A simple policy can therefore use four practical groups:

Fast-moving, repair-stopping | Hold a controlled minimum and review frequently

Fast-moving, easy to replenish | Hold lean stock with an automated alert

Slow-moving, high-value | Buy against an approved booking or deposit

Slow-moving, low-value | Hold only where supplier lead time or minimum order makes it sensible

Review the classification with actual usage, not memory. Device popularity, part reliability and supplier availability change.

Calculate a reorder point

Start with:

Use the same time unit throughout. If a screen averages 2 units per trading day, normal lead time is 3 trading days and the chosen safety stock is 4 units, the reorder point is 10:

(2 × 3) + 4 = 10

When available stock falls to 10, place the planned order. Available stock should normally exclude units already reserved for approved jobs and quarantined units awaiting inspection.

Safety stock is a business decision, not a universal percentage. Base it on demand variation, lead-time variation, cost of a stockout, part value and risk that the model becomes obsolete. A part with volatile quality may need a supplier solution rather than more stock.

Set an order quantity and ceiling

The reorder point says when to order; it does not say how many. A simple min-max approach is often sufficient:

Cap the maximum using cash, shelf life, model demand and supplier return terms. Bulk discounts are not savings if the surplus is later written off.

For parts bought against a specific job, reserve them immediately. A unit that is physically in the building but promised to another customer is not free stock.

Use one receiving process

Do not make a supplier delivery available at the bench until it has been received:

  1. Match the parcel to the purchase order and supplier invoice.
  2. Count units and confirm exact model, tier and colour.
  3. Inspect packaging and obvious damage.
  4. Test parts where the business has a documented incoming test.
  5. Record batch or serial details where useful.
  6. Label and place the item in its recorded location.
  7. Quarantine discrepancies and notify the supplier within its claim window.

The person receiving should not silently substitute a different part tier because the ordered line is unavailable. Change the purchase record, pricebook and customer offer where the difference is material.

Allocate parts to jobs at the bench

The stock movement should happen when the part is issued or fitted, according to the shop's defined policy. Record:

  • job reference;
  • SKU and quantity;
  • technician;
  • date and status; and
  • removed-part or failed-part outcome where relevant.

If a technician takes two screens to the bench and returns one, record both movements. Avoid end-of-day memory entry: it creates negative stock and hides fitting damage.

Keep saleable stock, customer-owned devices, removed components and waste physically distinct. The same drawer should not contain a new battery, a swollen removed battery and a customer part awaiting approval.

Control failed parts and supplier returns

Use statuses that explain where value went:

  • failed incoming inspection;
  • failed during fitting;
  • failed after customer use;
  • wrong part ordered;
  • supplier return authorised;
  • supplier credit received;
  • scrapped or sent to an authorised waste route.

A return is not complete when the parcel leaves. Reconcile the replacement or credit to the original purchase and part. Track supplier outcomes by SKU and batch so repeated faults are visible.

The OEM and aftermarket parts guide provides a verification record for part-source and calibration decisions. The warranty policy template covers the customer-facing claim trail.

Count stock by cycle, not only at year end

Count a manageable subset frequently:

  • high-value and fast-moving items weekly;
  • other regular stock monthly or quarterly; and
  • all stock at the formal period end required by the business and accountant.

For a controlled count:

  1. freeze or tightly control movements;
  2. count physical units without looking at the expected number first;
  3. recount material differences;
  4. identify the cause before posting an adjustment; and
  5. retain the count, approval and adjustment trail.

Useful difference reasons include wrong location, issue not recorded, return not credited, receiving error, fitting damage and theft. An unexplained “stock correction” restores the number but does not fix the control.

GOV.UK requires limited companies to keep records of year-end stock and the stocktakings used to calculate it. See company and accounting records. Confirm the valuation method and tax treatment with the accountant.

Manage obsolescence deliberately

Run an ageing report showing the last receipt, last use, quantity and stock value. For each inactive line, choose a documented outcome:

  • retain because demand is credible;
  • return under supplier terms;
  • transfer to another location;
  • use in an approved refurbishment;
  • sell with an accurate description; or
  • write off and use an authorised waste route.

Do not keep stock merely because writing it off makes the month look worse. The cash has already left; the decision is whether the part still has a supportable value and use.

Store batteries and waste safely

Lithium-ion batteries create safety and waste-handling risks. Quarantine swollen, damaged, overheating or leaking batteries from saleable stock and follow a documented risk assessment, insurer requirements and the instructions of the authorised waste contractor. Do not give generic internet storage advice priority over the conditions for the premises and quantity held.

The Environment Agency's current guidance for permitted waste-battery facilities discusses separation, inspection and fire-resistant containment for relevant operations. It is not a one-size-fits-all shop instruction, but it shows why damaged battery storage needs specialist assessment. See waste-battery storage and handling measures.

Check whether the business must register as a waste carrier, broker or dealer and whether an environmental permit or exemption applies. Start with the waste carrier registration service and environmental permits guidance. Rules and regulators differ across the UK nations.

Protect bench staff

Inventory control also includes consumables and substances used in repair. Keep safety data, usage rules and replenishment for adhesives, solvents and soldering materials.

The Health and Safety Executive warns that rosin-based solder flux fumes can cause occupational asthma and says exposure must be assessed and controlled. Its solder-flux fume guidance covers risk assessment and control measures.

Do not wait for a technician to improvise when an extraction filter or protective item runs out. Treat safety-critical consumables as repair-stopping stock.

Measure a small set of inventory controls

Use definitions that stay consistent:

  • Stock accuracy: correctly counted lines divided by lines counted.
  • Fill rate: approved jobs for which the required part was available when promised.
  • Stockout count: jobs delayed or lost because an expected part was unavailable.
  • Return rate: supplier returns divided by units received for the same SKU or tier.
  • Warranty part rate: replacement parts used for warranty work divided by original jobs.
  • Inactive stock value: recorded value of parts with no movement beyond the chosen period.
  • Emergency purchase cost: premium delivery and price paid because the normal control failed.

The numbers are signals. A high stockout count may be a reorder setting, receiving delay or inaccurate reservation problem. Diagnose before raising every minimum.

Inventory software checklist

Before adopting or changing a system, confirm that it can:

  • distinguish available, reserved, quarantined and on-order quantities;
  • connect a part movement to a repair job;
  • preserve supplier, batch and cost history;
  • record stock transfers, returns, credits and write-offs;
  • enforce role-based adjustments;
  • export a full movement ledger and period-end quantities; and
  • show who changed a record and when.

Run a sample through the complete path: purchase order, receipt, reservation, fitting, customer warranty return, supplier return and credit. A glossy dashboard is irrelevant if one of those steps needs an off-book spreadsheet.

30-day implementation

Week 1: define SKUs, locations, statuses and who can adjust stock.

Week 2: count high-value and fast-moving parts; resolve the largest differences.

Week 3: calculate reorder points for the small group that drives most usage and repair delays.

Week 4: test receiving, job allocation, warranty return and supplier-credit workflows end to end.

Then expand by exception. Do not attempt to perfect thousands of dormant lines before the common parts are controlled.

Use the repair shop accounting guide to reconcile stock with financial records and the phone repair pricing guide to feed current landed costs into quotes. Cellbot can connect jobs, parts and pricebook records; verify the current capability on the features page.

What changed on 26 August 2026

The page was rebuilt around stable part identity, status-controlled availability, reproducible reorder arithmetic, receiving, job allocation, returns, counts, obsolescence and battery/waste boundaries. Unsupported universal stock levels and software promises are excluded; a downloadable control register and original inventory loop were added.

Sources and method

The reorder and min-max methods are original editorial operating examples, not industry benchmarks. Obtain qualified accounting, safety, environmental and insurance advice for the business and premises.