shows that it's in one's toolbox, and it really shouldn't be.

Why?

In my real toolbox I have one of those universal spanners beloved of TV commercials: "Replaces every spanner you've ever owned". An unwanted christmas present from a well-meaning relative nearly twenty years ago, it's still there because there is one darn nut on the timing chain cover of my car that is so awkwardly positioned that it's damn near impossible to undo. Using ordinary spanners (wrenches), I have to alternate between a straight ended and an offset to undo the thing. About 15 degrees at each bite. Since it needs about 5 full turns to undo, it takes forever. But using that stupid universal, because it will grip even on the angles as well as the flats, it acts much like a rachet, and is far quicker. I have to replace the nut with a new one each time, but its small price to pay for the removal of the frustration.

On the same car, the side skirts are held in place by M10 hex head, self tappers. But several of them are sunk so deep into the plastic moulding that you cannot get a standard M10 socket onto them. It is too large to go down the hole. I looked around for ages trying to find a tool that would fit. Even a normal box spanner wouldn't fit. Then I was in a store that sell push bikes and saw a cheap and nasty toolkit for bikes, that contained a couple of very thin steel box spanners, one of which was 3/8th inch AF. Not a perfect fit for a M10, but it was thin enough to go down the holes and undo the bolts. It does the job.

As an aside, I asked at the dealers how they undo the darn things and they told me that there was a special tool available from the manufacturers. But, they are thin-walled chrome vanadium castings, and frequently, when a vehicle had been through a few winters and the bolts are rusted in, they crack and become useless. Their answer to having to re-order and wait six weeks for delivery of an expensive (£22 10 years ago) and fragile tool?

They use a short piece of 15mm copper heating pipe. Flare the end a little by waggling the nose of a pair of long nosed pliers in it. Drive it over the nut with a club hammer and use a pair of stilsens to undo it. Occasionally the copper just rounds out and they trim the end off and repeat the procedure. At £5 for a 3 meter length, it costs about £0.20 a time!

And that's the point. Sometimes the "wrong tool" is the perfect fit for the job. Ignoring what works for a specific case, because of some theoretical limitation in the general case is silly.

I was bitten by the %d format once when playing with file offsets in huge files. But that's the only time. Ignore the flexibility of formatting sprintf gives me because of one time in 6 years (with Perl) and 25+ in C? No way.