We didn't have a limit when we started, because we thought our issues were a lot simpler than they turned out to be, so had every expectation of it working quickly.
Then when our first sperm donor provided 5 straws, we knew we were going to use all 5 before stopping.
We then moved to anonymous donor, and our clinic lets you have 3 tries before going back to the bottom of the list. We asked if we should re-enter the waiting list as soon as we commenced with those tries, so that if they failed we wouldn't have to wait long before we were back at the top, but FS said (given the previous results) that if it didn't work in the 3 goes then we should stop using my eggs too.
If our last anonymous donor cycle hadn't worked (stim #8), we were going to try 1 stim cycle using SIL and my brother as donors.
If that didn't work we were going to go on the embryo waiting list.