My habit has always been to spend a couple minutes carefully and completely brushing out every piece of the grinder clean with a stiff brush before I even touch the herb I just dumped out of it. I'm sure that contributes to me going much further between cleanings than many people. I've never seen a friend carefully brush their grinder out after use as I do. I literally carefully go around every tooth.
*edit*
Here's a pic of what mine looks like after over a year and a half of use for ~98% of my grinding, with my carefully brushing it out after every use (makes a HUGE difference). Also, for reference, my herb tends to sit in sealed containers with 62% Boveda packs for months before I ever get to it (I like to buy ahead):