Depending on what I’ve mixed up, I might sort by diameter using go-no go holes in a strip of metal – although eyesight is usually sufficient.
Go and no-go threads are useful. Metric set on one side, with Imperial as at least two sets on the other.
A lot of my imperial stuff is UNx, so those need sorting from Whit.
Screws are sorted into wood and machine types, then sorted further as required.
Washers are never quite big enough – the metric/imperial clearance problem. But often cheaper to buy 100, than just a few….
A long and tedious process but worth it if one has the time.
Drills are yet another issue. Those are often sorted into approx sizes in standard, longer and short (stub). The caliper then comes in handy for selection of a suitable item, which then likely gets deposited in the sharpening tub – usually while looking for a replacement for one of the boxed drill sets.
Buying (local) is easy for metric, but not for imperial, these days. But there is a lot of tat sold both locally and on line.
I’m like Robert, but my really useful boxes are mostly the shallow variety, marked but not cataloged as well as his. Mine are mostly on shelves, in steel cupboards, so while only 3 high on each shelf, it is usually the bottom one that needs to be extracted.
One-offs is sometimes a bit of a problem, but compounded if a set of several are required.
I fully expect/accept my ‘collections’ will be bought (like a lot of mine were) as a ‘job lot’ at an auction when I’m gone – or thrown in a skip.