Flat mouse accel is fairly obvious.
Hi-Res scrolling is an option that is useful on certain mice that technically support 'pixel-perfect' scrolling, but still 'click' like regular mice would when you scroll. Some mice are designed to use pixel-perfect scrolling, so keeping it optional is useful.
if the list of device names is the same with a devices update event
then assume its the same as before and dont go probing all their
properties which takes time and round-trips which is not good.