I think the site used to log me out something like every 24 or 36 hours ... but more recently it seems to be every several hours? Not a huge deal, but a bit annoying. Was there a deliberate change at some point?

No changes on our end.

-RJ

i can't report similar problems either.
it's been remarkably stable for me over the last week or so.
probably because i am on holiday and not logging in from @home and @work <.<

I figured out my issue.

The frequent log-outs were on my phone, and were whenever I changed network/carrier (Home wifi to cell-carrier to work wifi when I walk to work in the morning, on and off work wifi if I take a walk at lunch, etc).

Something about the authentication here is set differently than other boards that I frequent, and seems to look at that and not just the hardware I'm holding in my hand.

Now that I've figured that out, doesn't bug me as much -- I know when I'll have to log back in.