I leave my #GrapheneOS 'Auto reboot' option at 18 hours. To be honest, 12 hours might be viable as well, anything less than it would start being inconvenient. What about you?
Discussion
Really depends on the use habits of some people. I use my phone for long uninterrupted periods then leave it off for many hours, so in that case I use 30 minutes and it doesn't disrupt me. It was moved from 72 to less since a value less than that would not get in the way of a lot of people. We consider the default reasonable.
I think my super low time is due to me not having socials where I require constant notifications though.