If an infant seat doesn't meet your needs, the alternative is a convertible seat, which accommodates both infants and toddlers through a single purchase. That's because a convertible seat, which is required for children over 20 pounds, can accommodate infants from 5 to sometimes as high as 30 pounds when used in the rear-facing position.

Unlike infant seats, convertibles cannot be used as carriers or rockers, and are not compatible with stroller systems.

Note: Pediatricians and child care advocates recommend that you keep your child rear-facing up to a year of age and 20 pounds. However, some children under one year of age can weigh more than 20 pounds, and some convertible car seats on the market are not rated for use rear-facing over 20 pounds. You can follow your pediatrician's advice, therefore, only if your convertible car seat has been rated by the manufacturer for rear-facing use over 20 pounds.

When your child outgrows her infant seat, the right car seat for your child is a convertible car seat. Convertible seats are so called because they can generally be used rear-facing for infants from 5 to 30 pounds, then converted to a forward-facing position for use with toddlers 20 to 40 pounds. Convertible car seats are available in two main types: the overhead shield and the five-point system. Their primary difference is the restraint systems, from which the seats get their names. The best way to decide which type of seat will be best for you and your child is to go to the store and examine each type of restraint. This type of car seat has a shield that swings down over the child's head and snaps into place between the legs. The shoulder straps are conveniently placed upon the child's shoulders with minimal adjustment. Simplicity of use is why the overhead shield is the most widely used convertible seat. The five-point type of convertible seat uses a harness similar to the one used in racing cars, with two belts located over the shoulder and hips and one at the crotch. Many child care advocates recommend the five-point restraint system. Accordingly this seat is enjoying increasing consumer acceptance. Once you decide which type of seat you plan to purchase, your next step is to determine which features are important to you and your child. These basic features should be present on any convertible seat you choose:

		Up-front harness adjuster
		Up-front buckle-release button
		Three-position adjustable shield (on overhead shield-type seats)
		A minimum of two recline positions
		Plastic belt guides in the pad, to make harness adjustment easier.

Once you've considered the basics, you'll want to think about these aspects of the seat (more-detailed descriptions follow):

		Comfort, quality, and coverage of the seat pad
		Pillows and inserts
		Belt-track system for easy installation
		Seat-saver base
		Up-front recline adjuster

Comfort is the most important aspect of the seat pad. Try prodding and poking various seat pads, and imagine yourself riding in the seat. Which seat would you prefer to sit in during an eight-hour trip to Grandma's? The quality of the seat's material will often vary depending on the cost of the seat. More-expensive seats generally have plusher, more durable fabric that will hold up to wear and tear better and will fade less. Finally, you'll want to check out how much of the plastic seat shell the pad covers. More coverage should offer more comfort for your child, of course, and will be more aesthetically pleasing. But the more material used in the seat, and the better the quality of the material, the higher the seat's cost. Optional pillows and lumbar inserts also increase your child's comfort. A convertible seat must be big enough to accommodate up to a 40-pound child; therefore, lumbar supports and pillows are available on some models so that a toddler as small as 20 pounds also can be comfortable. All convertible seats recline, but more-expensive ones have the seat-recline adjustment conveniently located at the front of the seat. Some even allow you to adjust the recline without releasing the seat belt. You'll also want to look for the number of recline positions (some seats offer more than two). Moving a car seat from car to car can be time-consuming, especially with the early-morning day-care crunch. A few seats, such as all harnessed Evenflo seats, offer the BeltTrac™ System which allows easy access to the vehicle's seat belt from the front of the car seat, eliminating the need for you to pull the vehicle's belt through the back of the seat. The best way to understand what a BeltTrac System offers is to install into your car a friend's car seat, or some store display models, then try a seat with a BeltTrac. You'll see that the difference is worth it. When installed in the same position in a car for many months, some car seats leave indentations and wear marks. To avoid this, you'll want to look for a car seat that offers a seat-saving base, which reduces wear and tear on your auto seat cushions. A key reason to consider a convertible seat for your infant is the monetary savings you will realize by purchasing only one seat. In order to expose yourself to options and features you otherwise might have missed, make price your last consideration when purchasing a convertible seat. After all, $10 or $20 extra could provide you and your child with features that will save you time and provide more comfort for your baby. (And since your baby could spend up to four years in this seat, time and comfort are important commodities.)