Drill bits wear usually begins at the corners of the drill, as a slight rounding.
The cutting edges or lips and the chisel edge begin to wear at the same time.
Because of this the surface has no clearnce and tends to rub in the hole rather than cut.
This wear increases the amount of power needed to force the dulled edge into the work, causing increased heat generation and faster wear.
There are two ways to remove worn portions.
If the ware is minimal, lightly regrind the drill point surfaces
For more severe wear-when the drill body is worn back 1/4" or more-cut away the worn areas with an abrasive cutoof wheel, then restore the original point angle.