You want to raise enough to serve its purpose, which is to thin the field. So the stakes you are playing, your position, and the number of limpers, and table texture should be taken into consideration.

If 4xBB is getting the field down to HU or 2 others most of the time then thats probably the correct number. I play 100nl I raise 3x BB with no limpers, I add $1 (bb) for every limper. If this doesn't work to thin the field regulary I go to 3.5bb.

At any table depending on the number of limpers my raise can be 3xbb to 6xbb.

My cards are not in the equation.