What do you consider acceptable PBEM turnaround?

[Wdll]

Till mid September I have all the time in the world, so I can play several turns per day without a problem. In fact winSPMBT is the only game I play now, together with online Renegade, though I do have thousands of games.
After mid September, I will be able to play at least one turn per day, some days more, but not as many as now.

I have 4 running PBEM games, 5 my max so far, and one of them sends a turn every couple of days, one every day one turn, one 1-3 turns per day and the last one 1-5 turns per day. All acceptable of course. If the opponent doesn't have the time I can accept playing only one turn every 3-4 days, but if it goes even more than that, I might have an issue playing with him/her again since by that time I will have problem remembering everything about the game in progress.