At most I've done spinning about three times a week. My legs otherwise need a bit of a rest or some variety. Even when I was riding 200 miles a week, spinning just took more out of me. This time a year, I'd rather be outside than in the gym though, but if it works for you, then great. I will say that you might want to mix it up a bit more. In my experience, the limited range of motion that cycling generally requires can lead to some muscle imbalances or weakness that, in turn, can ultimately lead to injury or disfunction. You might add in some Pilates, Yoga or the like to make sure you're well rounded, so to speak.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher