It seems like each person needs to find their own balance. I know some officals, young and old, that can work 5-6 nights/days a week a still be fresh the next day, while there are others that work 2 or 3 days and still need to cut back
To me, the hardest nights are the ones where I have to do a JV and V game. I know there are many of you now rolling their eyes, thinking, "What a wimp! That's all I do every night!". But the hardest part for me is not the physical part, but the mental part at the beginning of the second game. You get into a certain flow of the first JV game, get used to the players, etc. When you come out for the second V game, the uniforms are the same colors, but the players are (usually) faster and better, and the game is entirely different. It's hard to switch gears for those first few minutes. I've found myself more drained at the end of those nights than at the end of a single game double-overtime nail-biter. In fact, 3 nights a week of those double games is enough for me, while I can easily survive 5 nights of single games, even at the college-level.