[PROBLEM] System freezes after a while

[aknaggbaugh]

I had a similar problem, but it took longer than an hour to occur and seems to have been caused by my moving /var/cache into RAM to save wear on the SD card. I reverted that change to the standard moode setup and it has worked fine ever since. Have you changed anything like that, if so that might be the problem: I was getting kernel error messages relating to trouble allocating memory, so the 1GB RAM on the Pi 3s isn't enough for such changes, it seems.