Freeze is a fairly exceptional time unless something goes wrong; most of the the time it’s:
Stable if you’re running a server, something boring and important where security is paramount and it’s okay for the software to be kind of old
Testing for daily use (personal machines etc)
Unstable / sid is also fine for daily use most of the time, although once in a blue moon something important might break. It mostly behaves like testing; the only reason you would choose unstable is if you’re actively developing for Debian or else if it’s so important to you to have extremely up-to-date software that you can accept some brokenness.
I recommend testing for normal machines and stable for servers.