The biggest single waste in a tool box is the cheap drill-bit set bought for one project and then expected to drill anything. Drill bits are split into families for a reason, and using the right family transforms both the speed of the cut and the working life of the bit and the tool. Four families cover almost every job that comes up in DIY and trade work.
HSS — high-speed steel — is the general-purpose bit. HSS-G is ground for accuracy and runs straight in mild steel, aluminium, plastic and softwood. HSS-Co is cobalt-alloyed and is the right choice in stainless steel and hardened steel. Cheap HSS-R bits are rolled rather than ground and will skate on a polished surface; HSS-G is a better starting point even for occasional use. The full HSS and cobalt range sits under drill and screwdriver bits.
Masonry bits use a carbide tip brazed onto a steel shank. Standard masonry bits go in a regular drill chuck and handle brick and softer concrete in rotary mode; SDS masonry bits use the spline-shank fitting on hammer drills and are the right choice for harder concrete and the bigger holes. Match the bit to the drilling mode — a hammer bit in rotary-only mode will glaze, and rotary masonry bits used in hammer mode will shatter the tip.
Multi-material bits use a sharper carbide grind that takes brick, tile, light metal and wood without changing bits. They are excellent for kitchen and bathroom fit-outs where the material changes constantly behind the tile face. For wood specifically, brad-point and spur bits cut a cleaner hole than a standard HSS twist bit; auger bits handle the deeper holes in joinery work.
Whatever bits you fit, make sure the chuck is clean and the bit is fully seated. A bit that slips in the chuck wears the chuck jaws and the bit shank together. If the drill itself is tired — weak, sparking, or stopping under load — brushes are the first thing to check. See carbon brushes for power tools for direct fitments by brand.