I know you might be a boy but still. People get hair on their leg because it grows naturaly.
You have hairs on your legs to keep you warm and because we all used to be animals and we have not evolved completely to a stage were we have no hair.
so that we can shave them
They're not whiskers, they're reinforced hairs similar to whiskers. Not only are the hairs located on their front legs, but also over their eyes.
cause you dont have a head
yes.
Yes.
diving beetle
yes they have tiny millimeter hairs on their legs.
yes. they hear by using the hairs on their legs.
Yep amount varies
hairs to grab uneven edges
They are like feelers on snails
The hairs on a spider's legs are used primarily to smell. Spiders don't have ears, noses or taste buds, so they rely on these hairs to sense their surroundings, if something is moving nearby, and if something is edible. These hairs are called thrichobotria.