Agree 100%. Recovery is absolutely key to becoming stronger. You don't get stronger during the workout, but after, when your body rebuilds. Listening to your body is crucial to knowing when you've done the appropriate amount of damage (and yes, working out is damage) that can be recovered. Also knowing when you've actually recovered enough to do the next workout is really important. This is why weightlifters rotate their muscle groups, to allow more time to heal and rebuild. You can't really do that with your legs, especially cycling/spinning, so you have to learn how to recover. And really, after some initial phase, cycling is more about cardio vascular health than leg strength.