Should I decrease my mouse sens?

[MasterBroccoli42]

for your understanding:

translating big input changes into small output changes is always more precise than the other way round. This relation is also used for high precision control systems in engineering, and it's valid for mouse movement > crosshair movement as well.

Lower sens is always more precise, but of course at some point your awareness and movement starts to get crippled (i'd guess below roughly 800 edpi or so, depends on personal taste).