I tried to use my computer and exercise bike at the same time in the past but every time I got engrossed I'd slow down and not notice. Not really following your solution very well, but if I have to write this myself I suppose I will learn enough to eventually! Thank you. I wasn't thinking of a decay rate, merely having it run down through the gameplay actions, but the replenishment scheme could definitely benefit from a bit of flexibility to meet the needs of different users.