Years back it was popular to use HCG after 8-??16 wks and then continue another cycle.
The use like 4thad says is geting popular. Both work.
I've used 1000iu every 3 days @ end of cycle w/ Nolva, prior to 10-14 days of clomid (1 or 2 a day).
Hcg is great for strength like that. Powerfull stuff. I wont use it w/ out Nolva.