My current uptime is: up 9 days, it is bad for for the hardware?

I power down after each use. I like the idea of cleaning caches so that when I boot up and start a new task there is no overhead burden of old caches.

I turn both my laptops off during the night or when I'm at work. No need to keep them running when I'm not around.

One is a Lenovo IdeaPad running on Windows 10. The other is a 2017 MacBook Air. Both laptops have been running fine since I've bought them, 1,5 and 2,5 years ago.

I only ever restart if I have to (update or something like that). Otherwise my MacBook Pro is running constantly, sleeping when not in use.

When asleep, most things are not running, so no "wear" would occur.

All electronics suffer some degradation through time in use, but there is some concern about the hard changes that occur when you shutdown and restart being more detrimental than leaving it running. Everything changes shape when heated or cooled, so those changes may cause more stress than just letting them run at a fairly constant temp.

I don't know if there are any definitive studies that have resolved that question.

Before I go to bed each evening, I power down my Macs, and repower them when I get up the next morning. Been doing this for years, and the same Macs have had no hardware or software issues across updates or upgrades.

I never shutdown unless to update or troubleshoot. I also prevent the hard disk from sleeping when the display goes off, to allow background tasks to complete. Spotlight indexing, Photos uploads etc.