Which Debian distribution are you using, stable, testing, unstable?

I take care of a couple machines for family members. Those have Debian stable with automatic update (unattended-upgrade). I can't recall the system or packages ever breaking. At most users are a bit confused when an update change the UI a bit.

Sticking to stable and avoiding third party repos gives a pretty solid system. Only developers or sysadmins might consider Debian testing. Only people working on Debian itself should use unstable.