I had a girlfriend who used Debian back around 2005.
Never have I been around an OS that didn't work as often as Debian. It wouldn't crash, but need to be updated or something every hour. It was a full time job keeping it running for her.
Every hour was obviously hyperbole. It would break often. Normally due to some issue that would pop up, most often drivers.
She did run on unstable and had a fetch for updates automated every evening. Her goal wasn't a stable OS, but to be at the forefront of testing. She knew no programming, so it meant that she would report bugs and have a box with a giant fan that didn't run anything most of the time. She made bad choices.
I'm sure stable Debian is stable. I'm sure it's gotten better in the past 15 years, but the fact my experience with Debian was an unstable mess that was more of a job than a useable system makes me suspicious of the distro.
If you run testing or unstable there will be updates available very very often. But, you choose when to update, you don't need to update anytime an update is available.
You should know what you're doing and expect this if you're running it. Otherwise, you should use stable. With stable, you'll typically just have security updates until you choose to update to the next stable, which typically is released every other year.