I've been running testing on multiple workstations for over a decade and very rarely have issues. Just avoid updates right after the rollover to stable and you're good.

I have been running sid (unstable) on my desktop since 2013. I've had maybe 4 issues in all those years. This is through multiple ram, diak, power supply, motherboard upgrades. It just runs fine.

I've been running testing for quite some time. Runs well. Sometimes some smaller hiccups during the freezes. They don't promise you'll get security patches on time (with anything but stable). Otherwise nice rolling distro. I'm occasionally mixing in packages from unstable.

I have been running unstable for over a decade testing is just fine install apt-listbugs and apt-changelogs and keep an eye on mass removes when you do an upgrade and you will be just fine. also timeshift is your best friend.