A dull bit is expensive in a quiet way: more pressure, more heat, more broken screws, more ruined holes. Most bit damage comes from wrong speed and too much pressure, not from hours of use.
Match speed to material
Wood tolerates high speed and light pressure. Metal wants slow speed, steady pressure, and cutting fluid. Masonry wants a hammer drill and a carbide tip, with the drill in hammer mode only.
Let the bit cut
If you are leaning on the drill, the bit is dull or the speed is wrong. Overheating blue-tints a bit and softens the tip — at that point it will not hold an edge.
Sharpening twist bits
A bench grinder or a dedicated bit sharpener can restore the 118-degree point angle. Keep the original angle, sharpen both flutes evenly, and cool the bit in water often so it does not lose temper.
Storage
Bits knock against each other in a loose box and dull at the tip. Use an indexed case or a bit block, and keep a spare of your most-used sizes — 1/8, 3/16, and 1/4 inch for general work.
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