Hi,
Thats a difficult question. I get overwhelmed at times but I enjoy the number of sets coming out. However I collect a couple of areas that they arent producing right now and I am still working on one set from the Durbar. That said I will probably get into the VC series and get some of the Red Coats as well but right now I'm trying to maintain my focus on finding some sets that retired a while back. I do wish they would have slightly longer run times for some sets. As for the number of sets released per year well I would say they are right on target. It would get a bit out of hand if you collected a lot of different series like WWI, WWII and the ACW you could go bonkers and spead a lot of cash really quick. Now for WWII they released 15 sets (if you count the senics) so thats not so bad but if you add that many again with ACW you get out of hand real quick. So I guess my point would be focus on the sets that you like the best and dont worry so much about having all of them.
Have a great day
Dave