Phillips head screwdrivers come in sizes from 0 to 4. The lower the number, the larger the tip. Most jobs can be handled by a No. 2, like this 7-inch option from Klein.

Simply stroke a very strong magnet (from a hard drive works well) along the shaft to magnetize a tool. For a laptop or cell phone type repair, you should get a good set of screwdrivers.

JIS screwdrivers are available from sizes 000 to 0 (very small, precision-type screwdrivers for electronics) to 1 and 2 (more useful for motorcycles). Note that a JIS screwdriver will usually work on ...