Rotating the board will make it last longer. There has been a rumor going around for years that you should spray water on your board. It will ruin your board. I have seen some boards that were sprayed, and it isn't a pretty picture. The surface of the board begins to 'bubble' and fall apart.
Electronic boards differ slightly.
The outer ring closest to the black is double the number. The inner ring is triple the number. The outer portion of the bullseye is worth 25 and the inner is worth 50.