I'm 44 and not on juice so once every five days/ twice in ten days for squats if squatting heavy. I can squat once every three to four days with moderate loads. For heavy benching, about twice in eight days. I don't Deadlift often but when doing a training block with deads in it, I guess it would be once every five days.
I follow Hatfield's advice on the recovery time needed for various muscle groups when training for limit strength.