How many distros you checked before you knew what is the right for you?

I for myself checked dozens of LiveCDs.
It's not easy to decide but my favorites are:
Puppy,
openmamba,
Mandriva,
Knoppix,
Slax,
SAM,
Linux Da Vinci

and I still use them in different context.

How did you make your decision? You checked yourself or followed recommendation?