Zimerius: well you can change your dpi settings of course but the catch is, with even more finer movements the risk for RSI increases a ten fold, then you absolutely need to use a training hand pincher every day!
( this of course depends on day activities, shape, build and many more circumstances )
That won't work for me in most games I'm playing. I play a lot of games with first person perspective. Stealth, shooter, survival, RPGs... And I almost always play them 'sneaky'. The problem: I get pretty immersed and I'm one of those guys who gets jump scared by the tiniest things. High dpi means my character does a 720° turn every time I poop my pants xP
I have a Logitech mouse with some extra buttons. I tried switching dpi "on the fly", depending on what I need. I'm too stupid for that... Now I have a dpi/sensivity setting I can live with and have one button set to very low dpi when I keep it pressed. Helps with sniping (and with older games that are sometimes very sensitive in menus).
Sometimes I think about switching to a trackball, but... well... My mouse is still good ;)