You do not need 300 pieces to be prepared. A compact set of common drill bits and driver bits covers far more household work than a huge case full of duplicates and mystery accessories.
1. Ordinary twist drill bits
A basic range of twist bits handles many holes in wood, plastic and light metal when the bit material and job are appropriate. Keep the common small sizes easy to find because pilot holes and hardware projects use them constantly.
2. Driver bits that actually match your screws
Phillips, Torx and square-drive fasteners show up all over home projects. The exact fit matters. If a bit rocks around in the screw head, stop before you turn a reusable screw into a stripped metal circle.
3. Spade bits for occasional larger holes in wood
They are inexpensive, easy to understand and useful for rougher larger holes where a clean furniture-grade edge is not the main goal.
4. A countersink bit when screw heads need to sit neatly
If you build shelves, trim or simple furniture, a countersink can make the finished screw look much better and reduce the temptation to drive the screw too deep with brute force.
5. Specialty bits only when the project asks for them
Step bits, masonry bits, hole saws and Forstner bits can be excellent tools, but they do not need to live in every beginner kit. Buy the specialty bit because the material and hole require it, not because a giant accessory case happened to include one.
If a drill suddenly seems weak, check whether the bit is sharp and appropriate before buying a bigger drill or battery.
The small-kit rule
Buy the bits that match the materials you actually touch. For most households, that means common wood and light-metal drilling plus the driver bits found on furniture, shelves, appliances and deck hardware. Add masonry, tile, hole saws or specialty bits when a real project creates the need.
Keep duplicates of the tiny common sizes
Small drill bits are easy to dull, bend and lose. A set with sensible duplicates can be more useful than one with dozens of exotic one-off sizes.
Organize by job, not by marketing label
A small case for drilling bits and another for driver bits is often easier to use than a giant mixed box. If you cannot find the PH2 bit without emptying 150 pieces onto the floor, the kit is not helping much.
Replace worn bits without guilt
Bits are consumables. A $5 replacement can make a perfectly good drill feel new again. Keeping a visibly damaged or rounded driver bit because it came in an expensive kit usually costs more in stripped screws.
Sources used for this answer
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