I've used these on everything from WiFi Hot Spots to coffee thermoses that have been washed for years and the labels are still there and solid as the day they went on!!! O,O
I've used them for Serial Numbers and anything that might get loaned or lost and need a return #. Which has actually helped with everything from WiFi Hot Spots. To Bluetooth Speakers which have found their way back fairly consistently though occasionally after a few weeks.... They last almost forever and they're easy to make and apply. I also have an engraver, but to be honest it's results varied so much with the texture of the surface you used it on that I stopped using it.
I have a little sister that tends to leave her stuff at her friends houses a lot, so she gets a good bit of use from these. I also use them to keep track of everything from serial numbers to anything I don't want to ever fade, like Windows Keys. Though now with Windows 10 they're linked directly to your Microsoft Account even if you upgrade and tweak your system fairly regularly. I've put everything from a new motherboard for a new processor. To new GPUs, Hard Disks Optic Drives and Ram Sticks in since the Windows 10 release. It's so nice not to have to get a new 25 digit serial number from the automated support number every time I tweak something. Anyways, I've found several high wear and wash items that have had these labels on them for years and they still look great!!! ^_^