[userbinator]

Can you expect to leave a real 64 on for days or weeks and it will stay up?

Yes. These early computers found their way into various embedded control applications too, and I suspect there's quite a few C64s still in operation that way; they would've been replaced long ago if they weren't stable. An article occasionally appears when someone discovers this:

https://news.ycombinator.com/item?id=12604414