Personally, I started with a fairly simple EDC some years ago, then got a better EDC, and since then I've specialized a little for specific purposes.. I have a L0D for my keyring, replaced my EDC with a NiteCore DI because it has a very low low, which I need for Geocaching at night, and soon I'm hoping to get the new Fenix TK10 for a compact high output thrower for the times when I need that.
I don't have the budget to random buy lights, so most of my lights have a specific reason for purchase. That's not to say I make the best purchases sometimes, such as I got the L0D for geocaching only to realize it's low output was
quite high, 20 lumens or so, where I was looking for 2-3. I still keep it on the keychain with a 10440 battery for a super high output pocket rocket floody light.