I also experience a time-out after 30ish minutes of inactivity. I noticed a behavioral change a few months ago where Pinside no longer keeps me logged in, whereas prior to that Pinside always kept me logged in.

None of the other sites I visit regularly have this challenge (generally everything else stays logged in).

I figured it was a new security feature on Pinside and assumed it was the same for everyone. If I find some kind of setting (Pinside, Chrome, or otherwise) that allows me to stay logged in I'll share back with the thread.