We all land hard at some point in our derby career. Knee pads are one of those staple protective items that you don't want to skimp on. They protect your joints from impact, and the older you get, the more likely your knees will become a barometer, as you start to feel the repercussions of every impact you knees have ever experienced when the humidity soars. Let's treat them well!
When shopping for knee pads, keep in mind your skating style, how much impact protection you'll need, and how you plan on washing and caring for your pads.
Skate knee pads are typically sold in levels of amateur and professional. The basic protection you get from a cheaper, amateur set is fine for outdoor and recreational skating. They help with minor impact and prevent you from getting scraped when you fall. If you know anything about roller derby, you'll realize this is not enough protection for the sort of knee falls skaters undergo regularly. The pro-level knee pads are developed for higher impact situations that skateboarders dropping into half pipes experience. Thick memory foam cushioning with extra side impact protection come standard, and well worth the extra cost. However, this thickness also affects the profile, which can make crossovers and agility more difficult for many skaters. I find it best to start out with a bigger, well-cushioned knee pad for learning to skate, and once you've discovered your style, you can make the decision to upgrade to a slimmer knee pad designed with less bulky cushioning.
Another consideration is how the knee pads close around your leg. Certain designs use a neoprene sleeve that you pull up to your knee. The neoprene helps add basic compression and the pads are less likely to rotate during a fall, but they need to fit more accurately and can be a pain to pull off once you've been sweating. Alternately, many use an open design with velcro and straps that allow for breathability behind the knee. The benefit is that you can put your knee pads on when you're already wearing your skates, and have greater leeway for adjusting the fit. In order to prevent this style knee pad from spinning, consider purchasing knee gaskets or sleeves to wear under them. The gaskets provide extra support, compression to increase blood flow, and will help fill the space in your knee pad so it can't slip to the side during a fall.
The caps on knee pads will either be permanently held down with rivets, or secured with velcro or straps so they are detachable. Detaching the caps allows you to toss them in a washing machine to get the stench out, rather than washing by hand. Since we're on the subject, I highly recommend spraying your pads with a scented disinfectant spray after each practice, and hanging them to air dry. Leaving sweaty pads trapped in your gear bag causes stinky bacterial growth and even mold. We spend loads of cash on our equipment, so take proper care of it!
If you're new to buying knee pads, shoot for spending over $50 on a pair that will last through your first couple seasons. If you're a crazy-aggressive skater, expect to be replacing your knee pads every season.