Shopping for a cordless power tool? Today, besides brand name and features, the question is how many volts are desirable? How much power does the average person need? The first rule of thumb -- which you might have noticed -- is that as voltage increases so does the weight of the tool. Due to larger batteries, voltage today ranges from 9 volts up to 12 and 14 volts -- with the 18- and 24-volt models available on the high end. For most home projects, the smaller, lighter, and cheaper models are fine. The larger, more powerful ?work-horse? models -- designed for all-day use -- are for the pros. The right tool is purely personal preference -- how it feels in your hand, how much it weighs, and how often you'll be using it vs. its impact on your pocketbook. And that's the On The House tip for today.