These are some risks you take as a dancer, and some of them require lifestyle changes. Even though you probably like to keep your dance life and your home life separate, there are times the two lives fuse. It is these times when you need to be extra careful and think twice. Here are more things I've noticed that should be avoided:
Stretching without warming up.
Oh-so-dangerous, but one that most of us don't think about. How many times do you walk into rehearsal (or any type of dance-involved activity with no organized warm up) and just plop into a low second grande plie with your elbows propped against your knees? Or a lunge? Stretching cold muscles can lead to tears, strains, and ultimately even worse injuries. I'm not saying you need to do your full set of tendus and plies before you stretch, but do 20 jumping jacks, do a silly dance in a circle for 30 seconds, whatever will get your blood flowing a little before you start stretching.
Sometimes a partner is useful to push you in a way you can't push yourself, but be careful. Your brain is connected to your body via your own nerves. Your partner cannot feel your pain. Good communication is crucial or you will hurt yourself and possibly your partner. Unless you have someone you really trust and you really need someone else to help, avoid partner stretching.
Not staying warm.
Put on a jacket and long pants over that sports bra and booty shorts when you're not dancing, or you'll have to warm up again!
Wearing jewelry in class/rehearsal.
This is kind of a gray area - stud earrings are alright most of the time (watch the shoulder rolls), rings that are flush with your skin are usually not a problem, but items like bracelets, necklaces, dangly earrings, and large fashion rings can really hurt someone or cut into your own skin. Hoop earrings? Forget it - unless you're willing to chance it snagging on your clothes or someone's finger and having it damage your earlobe.
Not bandaging cuts/scrapes/wounds that have scabbed over and have not healed.
Dance studios are a great place to share germs - one person gets sick, everyone gets sick. You're constantly leaping in the air, rolling on the floor, touching the barre, and coming in contact with one another. Colds and flus are most commonly caught from studios, but blood or other bodily fluids (not sweat) on the dance floor can mean different and more serious diseases, like mono or athlete's foot. Bandage your open wounds and make sure you use antiseptic wipes if blood becomes involved.
Dancing through injuries - the dangers of "I'm okay."
'Nuff said - don't hurt yourself.
Sometimes it's good to tightly wrap/brace a strained body part in athletic tape/wrap/brace, but sometimes, such wraps just restrict bloodflow to an area that needs blood to heal. Check with a doctor or therapist if you have a chronic injury/problem that you constantly need support for and work with your teacher so that you don't end up hurting yourself more.
Sharing personal items.
It's alright to ask another dancer for a tampon or band-aid, but be more wary of sharing items like deodorant, tennis balls, and even water or food. They're great ways to transmit germs, rashes, and fungi.