If you look at some of the fertility studies and practices, they will have guys using 5000iu a day for months at a time. I think we have learned that to be a bit excessive.
Small doses, 250-300 max, is fine. I use to increase the amount if I began to atrophy, but the more I read, it seemed that it was better to add a third day as opposed to a higher dose, which is pretty common to what is done with HRT now. I still think you may need a little more on long cycles compared to trt but I seem to do fine with the low dose. Look at pregnyl, it comes with sterile water, because all 5000iu was intended for a single injection.
Adding hcg can help prevent lydeg cell damage. Someone has a link in their sig, "avoiding hcg burnout with NAC" or something similar to that. It's a good read.
I've used 1000-3000iu a day during the blast prior to pct. I have no permanent damage. Basically I just ended up with outrageous estro. 10 days is not enough time to cause permanent damage, but I'm not advising to use the doses I just listed, all that happened was I made pct more difficult because you will end up with estro from lydegs that is not effected by an AI. 500-1000 for the blast is plenty. I think most of us, I am guilty of this, don't give our bodies enough time to let the AAS clear before starting pct. 14 days after last inject is pretty common and really it should be closer to 21 days on long esters.
But I'm not waiting 21 days, it's to long to me and I start to crash, hcg is good during this time because it will elevate T as will aromisin. But I prefer during and before pct.
Sometimes, I will finish a vial during a cycle, then take a week off of hcg, then start up again. Now that I'm on TRT I do this as well. At least I try to stick to that but I will admit that there are times that I go thru 2-3 bottles without a break.