Freezing every two hours

I recently found my old ipod I got in seventh grade, and use it at work. I work at a warehouse, so it's long hours, but fast work. And the battery is definitely skipping performance wise after 11 years, but it still gets me through about two shifts on one charge, so that's cool. The thing is that after about two hours of nonstop playing, the music will just stop. I've got the toggle switch on lock, so I don't accidently mess with any controls with it in my pocket. When I pull it out and slide the toggle switch to unlock I can't do anything. It's still stuck on the kinda hibernate screen that shows the time and battery level. Nothing I do on the click wheel wakes it, so I gotta reboot it every time to get it back in and working. Which would be fine if I weren't working a very time oriented job where I can't keep wasting a minute to reset my mp3 player. I doubt there's a fix to it other than what I'm doing; and I'm sure it's most likely because of its age, but I'm just wondering if anyone knows why it's doing this. It never happened when I'd use it for hours on end years ago. I got it synced up to iTunes and updated, and accidentally reformatted it, which I'm sad about because I had a lot of good old stuff on it, but that's neither here nor there. It's up to date as much as it can be, and there's only a gig of stuff on it, with seven left.