If you're doing the work yourself and already have the door panel off, you may as well throw some lubricant on the track. I believe I've heard of people using graphite, but I just used petroleum jelly and it worked great for me. You can tell it makes a difference and helps the motor move the window easier. Lubing the track probably won't fix a completely stuck window (that's probably a dead motor or switch), but it's definitely helpful if the window is draining too much power.