I believe that the only "problem", is if people get too used to their standard sens. They think: "I have learned to live with this sens. So I'm gonna stay like this." Where fiddling around with it, trying new sensitivity settings might improve your overall gameplay.

So don't be afraid to try something new once in a while.

I have changed sensitivity loads of times since I got this mouse, to figure out what was best for me.

Well you're right till some certain point... Ofcourse you should find your best sensitivity first, but once you have one that you are comfortable playing with then you should keep it. If you are used to 1 sensitivity for a long time then you can react and shoot way faster than if you keep changing it. It's all about the famous routine...

I meant it more as Ocfos and Ultimate said that they didn't bother changing their sens in the first place, they just play. Which I think is a bad idea.. Well.. Not a great idea. By all means, if you have fiddled about and found something that works for you, keep it.

I just play