My recent experience is no – the first backup went just fine, but all subsequent attempts to add to it have failed, giving various errors in the logs, including mounting problems, timeout during the initial write test, bad database, etc. I did rename the drive between backups, maybe that was bad? The log shows Time Machine using the new name and finding the drive just fine.
Googling this I see that people have these same problems with external hard drives, though, so I’m wondering if anyone has been successful using a thumb drive and if there’s any trick to it.
On what time scale? I’m thinking it needs to last like a week, sitting in my desk drawer while I take my laptop on vacation.