Costs
Part of Needles, blades and irons: how mending tools fail, and what it costs
Deciding whether to service or replace a mending tool after ten years
When servicing a tool beats buying a new one, how to decide without a spreadsheet, and what a guaranty on a supply invoice is actually promising.
The maintain-or-replace decision comes up for shears, irons, machines and storage, and most people make it by feel. A rough ten-year view answers it in a minute, and it usually points at maintenance for shears, irons and machines and at replacement for mats, needles and thread. Treat the figures below as typical, not exact.
What to take away
- Cost per year decides it. Divide the repair cost by the years of remaining service, then compare that with the new item's price divided by its full life.
- Shears, irons and sewing machines are usually worth maintaining once. Twice, if it worked.
- Mats, covers and needles are never worth repairing, and a lot of people try.
- A guaranty on an invoice is a legal assurance about labeling, not about performance.
The calculation
Take the repair cost, divide it by the years of service you expect after the repair, and compare that against the new item's price divided by its full expected life. If the repair number is lower, repair.
Ten years is the horizon that makes the question concrete. By then a repairable tool, such as shears, an iron or a machine, has a service record, and a mat or a needle has failed more than once.
The number that decides it is the years of remaining service, and that is the one people guess badly. A serviced mechanical machine has decades left; a mat with grooves in it has months. Write the estimate down before you look at any price, so the price does not quietly set the estimate.
The usual result:
Typical figures: sharpening shears costs about $10 to $20 and buys about five years, so $2 to $4 a year. New shears at about $50 that last ten years cost $5 a year.
Service or replace by tool
Tool
- Shears
- Sharpen until pivot loosens
- Iron
- Descale; failed thermostat replace
- Sewing machine
- Service for decades
- Mat, cover, needles
- Replace always
Verdict
- Shears
- Iron
- Sewing machine
- Mat, cover, needles
Retrofitting beats replacing more often than people think
The instinct to replace a whole system rather than fix the failing part is not unique to households. The National Park Service leaflet on installing the retrofit gasket kit shows the alternative: a gasket kit on a decades-old museum cabinet instead of new cabinets.
The same leaflet warns that some pre-1980 cabinets used felt gaskets impregnated with arsenic or mercuric chloride, which are a health hazard and need careful removal.
Two lessons carry over. The failing part is usually small, and old equipment sometimes contains materials you would not choose today. Both are worth checking before you spend.
What a guaranty covers
Supply invoices sometimes carry a guaranty, and it is easy to read more into it than it says. The rule setting out the form of separate guaranty gives suggested wording for guaranties under the Act.
A guarantor in the United States puts it on an invoice covering the marketing or handling of textile fiber products. The general form guarantees that the products specified are not misbranded nor falsely nor deceptively advertised or invoiced.
That is a promise about labeling accuracy. It says nothing about whether the thread is strong or the fabric will shrink, which are the things you were probably hoping it covered.
Keep a simple log
Date, item, what was done, what it cost, and how long it lasted afterwards. Five entries make the next decision obvious, and it is the same log that supports the supply costing method.
Knowing which failure you are actually looking at comes first, and the failure modes article covers reading the work backwards to the tool.
