Originally Posted by violist

You're young. There will come a day when your internal clock no
longer reliably adjusts for time zones, daylight savings, and so on.
This will probably happen at the most inconvenient, unpredictable
moment. I'd suggest being prepared for that day with multiple
backups, even if you probably won't need them for years.

By the way, I've had abysmal luck with hotel clocks and both
manual and automated wake-up calls. Bring your own clock,
it's only a couple of ounces.