I agree with Tania, I probably do them all day long and never think about it.
One that comes to mind is every time I use a fresh roller cover, I put it on the handle, hold the handle between my knees, and run a piece of tape over it back and forth across the whole surface of the cover. This will remove any loose hairs or fibers that will get stuck to the walls.
And every time I break out a new brush, I run it under water (for latex) or dip it in some thinner (for oil) and spin them back out. It keeps the paint from drying up in the heel .