Repair or replace equipment: a future cash-cost comparison

Repair or replace equipment by comparing future cash flows over the same service horizon, not by trying to recover historical spending. Leave with two net costs, a repair-quotation threshold and a saved record of the assumptions that could reverse the result.

Updated: 29 October 2026.

What decision are you making today?

Repair or replace equipment is a decision about an asset you already own. Start with today’s alternatives: repair and retain the existing machine, or dispose of it now and acquire a replacement. Do not bring a rental-versus-purchase worksheet into this decision without changing its inputs. The buy or rent comparison addresses acquiring equipment rather than retaining an existing asset.

Define the service first. A small packaging workshop might require a machine to complete the same work at an acceptable quality for the next twelve months. Both alternatives must actually deliver that service. If repair feasibility, capacity or safe operation is unknown, obtain a technical assessment before treating either column as available. A lower calculated cost cannot establish that a repair is suitable.

Use one common twelve-month horizon beginning at the decision date. Assume both machines can serve throughout it. The replacement’s remaining value appears as a separate terminal sale assumption rather than an unexplained bonus for a longer useful life. This is a nominal cash comparison without discounting. It excludes borrowing, tax effects and a full long-term investment appraisal.

Remove historical spending, not present disposal proceeds

A sunk cost is spending that the present choice cannot change. Suppose the old machine originally cost 5,000. Paying that amount years ago does not make repairing it attractive today. Do not add it to the repair quotation. An accounting carrying amount is also not an offer from someone willing to buy the machine now.

The Open University distinguishes future cash flows that change between alternatives. ACCA explains why decision-independent historical spending and noncash depreciation do not belong in this narrow comparison. We use those principles, not either source’s numerical example. Every figure below was created for this exercise, not supplied by those sources.

An available disposal receipt today is different from historical spending. Replacing the machine lets you receive it now; retaining the machine forgoes that sale. We subtract the receipt from the replacement column. An equivalent opportunity-cost presentation could instead charge it to retaining, but do not use both presentations simultaneously. That would count the same difference twice.

Create a dated, hypothetical cash-flow table

All amounts below are fictional teaching inputs in one currency. They are not market quotations, an Anar engagement, observed client performance or achieved savings. The arithmetic has been executed separately; no repair order, purchase or equipment inspection has been performed.

Repair or installed acquisition is paid at the start. Operating and downtime amounts belong to the following twelve months. At the common endpoint, the remaining machine in each alternative is assumed sold. In the replacement column, the old machine is sold now and the replacement is sold at exit. These are different assets and different receipts, not two sales of one machine.

Downtime here means an additional cash payment such as temporary outsourced work. It is not gross sales revenue automatically treated as a loss. If you introduce foregone contribution or a different service interruption model, rebuild that line and avoid duplicating a loss already covered by outsourcing. The 300 and 100 are scenario assumptions, not reliability estimates.

Calculate both totals and independently reconcile the difference

Retain = repair + operation + downtime − terminal sale
Replace = installed purchase + operation + downtime − sale now − terminal sale

Retaining costs 700 + 1,200 + 300 − 100 = 2,100. Replacing costs 3,000 + 600 + 100 − 400 − 1,800 = 1,500. Replacement has a net comparison cost lower by 600 under this particular set of inputs. The conclusion does not establish that replacement is affordable at the starting date.

Check the result using changes rather than repeating the same column addition. Replacement increases the initial payment by 2,300, brings in 400 from immediate disposal, reduces operating payments by 600, reduces downtime payments by 200 and raises the terminal receipt by 1,700. The difference is 2,300 − 400 − 600 − 200 − 1,700 = −600. The negative sign means replacement is lower in this cost convention.

Jonick’s keep-or-replace discussion provides a framework for comparing alternative future costs. Our worksheet adds an explicit repair quotation and two disposal dates. Preserve the component amounts so another person can reproduce the comparison rather than trusting a single highlighted winner.

Find the repair quotation at which the result switches

Let R be the repair quotation and change nothing else. The remaining retain-column costs net to 1,200 + 300 − 100 = 1,400. Replacement remains 1,500. Setting R + 1,400 equal to 1,500 gives R = 100. This is a conditional equality point, not a rule that equipment repairs should cost no more than 100.

Test either side. At R=50, retaining costs 1,450 and is lower by 50. At R=100, the totals tie. At R=150, retaining costs 1,550 and replacement is lower by 50. These three tests help catch a reversed inequality or an incorrect sign on disposal proceeds. Technical feasibility remains a separate prerequisite in every row.

Now test the uncertain terminal receipt. If the replacement sells for only 1,000 instead of 1,800, its comparison cost rises to 2,300. With the original repair quotation of 700, retaining at 2,100 becomes lower by 200. This reversal is the important output: your preferred alternative depends on an unverified receipt. Do not hide that dependence behind a precise total.

If neither asset is sold at the endpoint, omit both terminal receipts: retain requires 2,200 and replacement 3,300 after the immediate old-machine sale. You then finish with different assets still owned. Those twelve-month cash amounts are not a complete lifetime economic ranking. Record that narrower interpretation instead of claiming the cheaper cash column proves permanent superiority.

Keep unresolved evidence and cash timing visible

For each input, record a dated quotation or an explicit hypothetical label. Check whether the repair includes parts and labor, and whether the replacement amount includes installation and delivery. Missing charges are not zero. If a real quotation omits a required item, save a question rather than a completed total.

Initial funding and net cost after terminal sales are different questions. A replacement supplier might require the full 3,000 before the old machine’s buyer pays 400. The terminal 1,800 cannot fund today’s payment. Use a cash-flow plan for payment dates and financing needs without assuming this worksheet has solved them.

Put spare-part availability, repeat failures and uncertain delivery into the business risk record. Use an equipment register for custody and readiness. Neither operational record replaces the repair assessment, and this calculation does not claim those checks were completed.

Save a reproducible fifteen-minute decision card

On Windows, open Notepad from Start and create a blank document. Open Calculator separately for arithmetic; Notepad is only the record. Spend the first part of the exercise writing the service requirement, common horizon and hypothetical inputs. Then calculate both totals, the difference bridge and the quotation threshold. Fifteen minutes is a suggested planning target, not measured completion time.

Decision date and common twelve-month horizon: [...]
Equivalent service and technical feasibility: [...]
Retain: repair / operation / downtime / terminal receipt: [...]
Replace: purchase / sale now / operation / downtime / terminal receipt: [...]
Retain 2100; replace 1500; replace-minus-retain−600
Repair equality 100; tests 50/100/150
Replacement terminal receipt 1000: replacement cost 2300
Input sources, dates and unresolved evidence: [...]

Choose File → Save As and save repair-replace-V 1.txt in Documents. Choose a new filename if that name already exists. Close the document and reopen the saved file from Documents in File Explorer. Check the 2,100 and 1,500 totals, the −600 difference, the 100 threshold and which asset is sold at each date.

Create a separate historical-price check: change the old purchase amount from 5,000 to 8,000 while leaving future cash flows unchanged. Your comparison should not move. Save the terminal-receipt sensitivity as V 2 rather than overwriting V 1. Link the conditional conclusion to a decision log with its assumptions. These are reader instructions, not a claim that we executed a desktop save-and-reopen test.