I saw one just the other day at work on my workstation. I wasn't doing anything, just left it on overnight as is policy (for AV updates, system updates, system scans, etc.) and it was BSOD in the morning.
The last time I rebooted my Mac was the last big system update. Otherwise I never even log off, just lock the screen, and I have five people using this system on different accounts (wife + kids). Right now I have four accounts logged on. It stays like that for months, and that never slows it down.
I do reboots as a matter of habit once every week or so and that I live by a field where lots of dirt gets blown around here in Phoenix. I just notice that my PC’s pick up an extraordinary amount of dirt here in Phoenix compared to other states I have lived in(except for EL Paso) so I have to do a little maintenance, don’t want a dirt clogged PC come the summer here that’s for sure.