Agreed. When I first started a couple of years ago, my school only offered 2 days a week. I couldn't stand the 5 days between thurs and tues. Finally they added a 3rd class. Still wasn't enough. Then a 4th. I took that too. Still not enough. Class #5 got added. I took them all and at that point I started noticing mounting fatigue and injury (I'm 36) from training so hard, so often.
Then class #6 was added. Not only do I NOT go to that one, but I'm being careful to periodize the other 5 days. 2 days a week I train very hard. 2 days a week are moderate and 1 day is ONLY technique drilling with MAYBE the lightest possible sparring.
This seems like a good balance as I'm now much less fatigued on a daily basis, my injuries have cleared up, my skill is on a relatively constant upswing and I look forward to every class; it never seems like a chore. I've seen a lot of guys come in going balls out 6 days a week only to disappear after a couple months.