Realistically, I only use it once per day ever, and then not all days- just when I really feel that i've got a good laundry list of things to get done. I never take it on weekends or on holiday (don't even take it with me). My ADD is pretty severe, but it was just formally recognized as ADD recently for me. If I don't have anything specific to do, then I don't take it and I suffer no ill effects (didn't take any to California & Burning Man for example)
I don't know why doctors prescribe it as a drug that can be taken every day. Not every day is equal, and every day is certainly not Side-project Saturday (best day of the week). :)
I recommend Vyvanse, the d-amphetamine prodrug with a therapeutic slope. Makes Adderall XR feel like a tweak with a trailing depression.