one small integer is not enough, two small integers are better (lab journal initials/number and sample number, like AC7-295. something like AC7-295A, then AC7-295B and so on if needed. that's how i do it anyway) this way there's no possibility of mixup with other people's samples and samples described in old lab journals

Allegedly

Yea but 2 keeps people from throwing it away during clean outs.

And people say pointers are hard.

Nearly, some identifier who it's from is also good. Without one? You can't complain if I throw it away at the end of the week cleaning.

But if they do get jumbled, sorting them back out into different experiments, batches or subjects or time periods might make you prefer some extra info accesible by eye.

If you've got a robot sorter maybe a qr code - but you'd have to be pretty large scale for that to be cheaper than a human.