You know you can use boiling water to sterilize bottles on the stovetop, so you may be wondering if you really need a baby bottle sterilizer on your feeding supplies list. After all, it's another thing to take up valuable space on a kitchen counter or cabinet.

But while bottle sterilizers may not be 100% necessary, many parents say they are for several reasons. Here's what to consider before adding a bottle sterilizer to your registry.

You should always sterilize a new bottle before using it, and if your baby is younger than 3 months, born prematurely, or has a weakened immune system, the Centers for Disease Control and Prevention (CDC) recommends sterilizing the bottle and parts once a day.

If your doctor recommends sterilizing the bottle between feedings, you may appreciate the convenience of being able to load and run the sterilizer without having to boil the water each time. (This is especially true if you're feeding multiple babies.)

A bottle sterilizer can also come in handy if you're traveling and staying where you don't have a full kitchen. Note, however, that you still need to clean the bottles and accessories before sanitizing them, as putting unwashed items in one of the devices can cause residue to build up.

Sterilizers all do the same job — sterilize baby bottle parts — but they have different functions that may appeal to different parents. Here's something to consider when you shop and sign up.

- Sterilization method. Most bottle sterilizers will use steam after you have added water to the tank. They can either stand on the counter (powered by a wall plug, battery, or USB cable) or put in a microwave, which will generate the heat needed to produce steam. Note that using distilled water will help prevent mineral scale buildup in steam models. Some countertop sterilizers may also use ultraviolet (UV) light to sterilize instead of steam.

- period length. Some models can get the job done in as little as two minutes, others can take up to 30 minutes. If you are using an older microwave with lower power, sterilization may take a few minutes (you can confirm this in the instruction manual).

- Drying function. Some bottle sterilizers also dry items after sterilization, which busy parents may find helpful. (And you can usually choose a "dry only" setting, which can be useful when you're still washing the bottles but don't need to sanitize them.)

- Store after sterilization. Some models also feature a "hold" feature, so they remain sterile inside for up to 24 hours after the cycle as long as the lid remains closed.

- Automatic shut-down. Sleep-deprived new parents often appreciate this safety feature on electric models.

- Size. Most sterilizers hold 4 to 6 bottles and may also have extra space for pump parts and pacifiers. You should also consider how much space it will take up on your countertop and whether you want to keep it outside for easy access or storage when not in use

- Compatibility. You know brands like Avent or Dr. Brown's will fit the company's bottles, but what if you want to mix them? Most sterilizers can hold a variety of different types of bottles, but when in doubt, check with the company, check what parents say online, or try taking one of your bottles to the store to see a floor model.

Baby Brezza One Step Baby Bottle Sterilizer Dryer

This sleek looking device doesn't just sit beautifully on your countertop. In just 8 minutes, it can sterilize up to 6 bottles plus additional parts like pump parts. It also dries them and is available in three cycle lengths: 30 minutes for smaller loads, 45 minutes (the usual recommended time), and 60 minutes (if you're dealing with high humidity or a particularly heavy load). After the cycle, the bottle remains sterile in the unit for 24 hours as long as the cap is closed. The adaptable design can accommodate most types of bottles, and you may also like the "dry only" feature when you no longer need to sterilize.

Weight: 5 lbs
Dimensions: 16 x 11 x 11 inches

Papablic Baby Bottle Electric Steam Sterilizer and Dryer

If you're feeding twins or triplets, you might want to go big with this large sterilizer-dryer combo - literally. One of the largest we've seen on the market, it's sure to compete for countertop space, but the convenience might be worth it. The unit can be set up in three different stacking configurations to hold up to 11 bottles or mixes such as pump parts, gutta-percha and pacifiers. It can be sterilized in 8 minutes or you can choose a drying cycle of 40 or 60 minutes. (There's also a "dry-only" setting if you don't need to sterilize.) If you want to leave the bottles in the sterilizer after the cycle, they'll last up to 12 hours as long as the lid remains closed.

Weight: 4 lbs
Dimensions: 13.1 x 12.1 x 8.7 inches

Nuby Natural Touch Basic Bottle Warmer and Sterilizer

Similar to the Béaba, this ultra-portable device can sterilize bottles and hot milk or baby food in minutes. It weighs less than 1.5 pounds, making it ideal for travel. Experienced parents say it can be adapted to different brands of bottles, including Avent, Mam and Dr. Brown. It also comes with a measuring cup so you can always add just the right amount of water.

Weight: 1.46 lbs
Dimensions: 5 x 5 x 8.5 inches

Philips Avent Premium Electric Steam Sterilizer with Dryer

Although small enough to fit on your countertop, this bottle sterilizer can do a lot. At its maximum capacity, it can hold six tall bottles, or oddly shaped items like pump parts and plastic utensils. It gets the job done in 40 minutes (10 minutes for sanitizing and 30 minutes for drying), and it also has a useful auto-off feature. After the sterilizer has finished running, you can leave items inside for up to 24 hours with the lid closed.

Weight: 5.29 lbs
Dimensions: 12 x 7.5 x 14.9 inches