There is a lot of information available on the importance of warming upand the benefits we derive from it.
Almost every class at the Academie starts with an instructor-led warm-up, featuring joint-movement, medicine ball-tossing and exercises.
Something that has always been stressed at the Academie, though not as publicized is what to do if our warm-up isn't appropriate for you. There are myriad reasons why you may not want to participate in the warm-up, the typical ones having to do with injury and/or stiffness (some students just want nothing to do with that ball). And that's OK. You don't have to do our warm-up.
But you should still warm-up.
If our warm-up isn't appropriate for you then carve out a little space for yourself where you can warm-up on your own. Or if a particular exercise we're doing isn't for you then substitute it for something else. I personally substitute burpees with lunges because my knees are a little fragile.
Cool downs are just as important. We've set up a quick cool down on our iPad that any of the instructors can fetch for you. I have a routine that I go through every evening when I come home.
Do warm-up and cool down; you'll thank yourself tomorrow.