Breast-feeding is a round-the-clock commitment. That's why many breast-feeding mothers consider breast pumps as important as car seats and baby wipes.

Whether you're going back to work or simply want the flexibility a breast pump offers, you'll have many choices. Some breast pumps are hand-operated, and others run on electricity. The designs also vary. Some models attach to only one breast. Others let you express milk from both breasts at once.

To decide which type of breast pump is best for you, ask yourself these questions.

If you'll be away from the baby only occasionally, a simple hand pump may be all you need. These pumps are small and inexpensive. You simply squeeze the handle to express the milk. You may even choose to pump one breast while the baby nurses on the other breast.

If you're returning to work full-time or you're planning to be away from your baby for more than a few hours a day, you may want to invest in an electric pump. Electric pumps stimulate the breasts more effectively than hand pumps. This helps empty your breasts and protect your milk supply.

Electric breast pumps are faster than manual pumps. If you'll be pumping at work or in other time-crunched situations, you may want to invest in a model that allows you to pump both breasts at once. Double breast pumps help stimulate milk production while cutting pumping time in half.

If the breast pump is difficult to assemble, take apart or clean, it's bound to be frustrating — which may reduce your enthusiasm for pumping. Make sure you can remove any parts of the pump that come in contact with your skin or milk for cleaning after use.

What's comfortable for one woman may be uncomfortable for another. Choose a pump that allows you to control the degree of suction. Some manual models allow you to adjust the position of the pump handle.

If you'll be toting the pump to work every day or traveling with the pump, look for a lighter-weight model. Some breast pumps come in a carrying case with an insulated section for storing expressed milk.

Some electric models are quieter than others. If it's important to be discreet, make sure the pump's noise level is acceptable.

Every pump has a shield to place over your breast. If you're concerned that the standard breast shield is too small, check with individual manufacturers about other options. If you want to pump both breasts at once, make sure the pump is equipped with two breast shields.

An electric pump needs to be plugged in. If an outlet isn't accessible, you'll need a rechargeable battery pack. Some models offer adapters that run on a car's cigarette lighter.

You can buy breast pumps from medical supply stores and most drug and baby stores. Manual models cost less than $50. Electric pumps that include a carrying case and insulated section for storing milk may cost more than $200. Some hospitals rent hospital-grade breast pumps, although the equipment that attaches your breast to the pump must be purchased. Because there is a small risk of contamination, borrowing a breast pump or buying a used pump isn't recommended.

Find out if your health insurance plan covers the cost of buying or renting a breast pump.

Ask for help. A lactation consultant can help you make the best choice — and offer support as you start to use your breast pump or if you run into trouble. If you haven't worked with a lactation consultant, ask your doctor for a referral. Counselors from La Leche League and similar organizations can help, too.