Practicing good hygiene is common sense, especially when it comes to feeding babies. But when it comes to pumping, what, exactly, does good hygiene entail? How—and how often—should you attempt to rid them of bacteria, mold, and viruses?

The difference between cleaning and sterilizing comes down to temperature and duration. Cleaning involves using warm, soapy water for a couple minutes, while sterilizing requires higher temperatures for longer periods.

There are two main sets of pump-cleaning guidelines, and they largely correlate with babies’ immune systems.

Babies with normal immune systems

If your baby is generally healthy, with a normal immune system, you should sterilize your pump before the first time you use it—and not worry about sterilizing it after that. You should wash your hands with warm, soapy water before every pumping session, as well as wash your pump parts with warm, soapy water at least once a day.

Because cold pump parts can inhibit letdown, it’s preferable to keep your pump parts at room temperature, says Dr. Laurie Jones, a pediatrician. When she was pumping, she says, she bought extra sets of pump parts.

Babies with compromised immune systems

If your baby was born prematurely, is still in the NICU, and/or has a compromised immune system, you need to hold your pumping and feeding hygiene to a much higher standard. That’s because your baby’s immune system is less developed and thus less capable of fighting off an assault, whether that’s bacteria, mold, or a virus. This means that you’ll need to follow a much stricter protocol that involves sterilizing your pump parts after every use.

There are a few ways to sterilize, including:

Where you clean your pump matters as well. In an ideal world, you’ll have a dedicated space for sterilizing, where you can be extra careful about what goes in the sink, where you put your bag and parts, what your arms touch, and so on. If you have to use your kitchen sink, it is critical to use a dedicated, well-labeled scrubber that never touches food, and to always wipe the surface down first to avoid cross contamination.

You’ll also need to keep your nails short, so they’re easier to keep clean (no fake fingernails), and wash your hands thoroughly before pumping and sterilizing (ideally, scrub up to your elbows).

If this feels like a lot, well, it is. Rest assured that premature (younger than 35 weeks) and NICU babies will gradually develop stronger immune systems; you don’t need to follow the stricter sterilization protocol when they’re ready to come home with you. And if your baby’s immune system is suppressed in the longer term (with a genetic immunology disorder or a cancer, for example), just remember that while you’re in the parenting game for the long haul, you won’t be pumping breast milk forever.

Let’s face it: Sterilizing every time you pump is no fun. It can feel exhausting, especially when you’re already exhausted, and it might feel scary, when you’re already scared. Try to be proud that you’re doing what you can to keep your baby’s immune system from having to fight anything. It’s a serious job, but this stage won’t last forever.