Purpose of Purchase: It all depends on what you intend to use the drill for when you plan to purchase a cordless drill. When shopping for the right cordless drill, you will find battery ranges from 2.4 to 36 volts and price ranges from $40 to $1000 or more. With such a variety of sizes and price ranges on the market, which is the right one for you?
Size Matters: Basically, bigger isn't always better. For general purposes, I recommend 9.6 volt to 14.4 volt cordless drills. An 18 volt or higher drill will feel quite heavy and awkward. Especially with prolonged project uses. A larger cordless drill will weigh 3 to 5 lbs more than a 9.6 or 12 volt drill. Higher voltage cordless drills provide more power, but are also more expensive.
Batteries: Nicad cells: named for the combination of nickel and cadmium components. These batteries deliver a constant charging rate and can be recharged rather quickly. Nicad batteries often can be recharged up to 1000 times before they need to be replaced. It is important that you don't throw your used battery in the trash. They contain toxic metals. You should take them to a battery recycling center.
NiMH: Which contains nickel-metal-hydride, are constantly improving in power and price. These batteries do not contain cadmium like Nicad cells, thus making them more environment friendly. NiMH batteries for cordless drills cost more than the Nicad batteries. NiMH batteries also have up to 50% fewer recharge cycles. When purchasing a cordless drill, check to see if you get an additional battery. If not, it might be a wise decision to purchase an extra one. How frustrating it can be when you run out of battery power and you have no back up battery!
Drill / Drivers : Many manufacturers offers drill / driver cordless drills. These are versatile drills which offer the option to drill pilot holes and to drive fasteners.
Considering all these options will help you decide the right cordless drill for your needs.