I have found it as a 'GENERAL' rule that if you make yourself pull your traps after the third day you will have enough seed left to have a good harvest the next year.Longer than that you are taking too many.After the third day your catch will drop off dramaticaly and won't come back anyway.
Problem with leaving seed is in some areas there might be another trapper or two waiting till you pull out and they kill your seed. Problem really got bad when rats hit 10 bucks. I once took a leak in my backyard and 5 minutes later there were two different trappers attempting to set 110s in the puddle...haha.
Our percentage was not that good though. To get those 16 muskrats on day 1 we had out almost 100 traps in 6 locations. The total check time took 2 hours. And so far we lost three rats to wring-offs. Two traps had front feet and one had a back foot.