The Golden Rule
Stick with one manufacturer, and you can use the same battery in all your tools-as long as they have the same voltage. So don't go for a 9.6-volt drill if you think you'll want an 18-volt reciprocating saw later. The descriptions below will help you determine how handy you really are around the house-and, thus, your future cordless tool needs.
The Unhandy Handyman
Symptoms: You're often hanging picture frames or wall sconces, and you're getting pretty good at it. But every time you try to actually build something, you end up abandoning the project or calling in a professional to clean up your mess.
What to buy: You'll probably never need a router-or is it called a grouter?-so stick to low voltages, anything from 7.2 to 14.4. You'll find drills, lights, screwdrivers, and other tools you can handle in this category.
The Occasional Fixer-Upper
Symptoms: Your work is more heavy-duty-you've learned to hang molding and have even built a few things that your wife lets in the house. You also keep busy outside, clearing leaves or trimming trees and hedges.
What to buy: Consider tools in the 14.4- to 18-volt range, in which you'll find powerful drills (for concrete, say), sanders, blowers, inflators, and saws.
The Serious Do-It-Yourselfer
Symptoms: You do some major DIY projects and may even have your own workshop. When relatives want to overhaul their rec room, they call you.
what to buy: You want tools of 18 volts or above-they'll give you performance akin to their corded counterparts. In this category you'll find circular, miter, and reciprocating saws, hammer drills, routers, and more.
Black & Decker's 14.4-volt Firestorm drill (top) features a removable head, under which is a powerful electric screwdriver.
Makita's line of cordless blowers (12 to 18 volts) are the only tools of their kind (middle).
Porter-Cable's 19.2-volt brad nailer, which buries thin nails without splitting wood, is designed for serious woodworkers.