DD1 - once I worked out that I ovulate late, two months
Next pregnancy - two months, ended in TFMR
Next pregnancy - five months, on clomid, ended in miscarriage
DD2 - one month, on clomid
It takes a very long time for my period to come back after an "event", 18 months after I came off the pill, 18 months after I had DD1. Hence the clomid after TFMR. So while conception was quite quick for me when ovulating, I had to wait a long time to ovulate for the first two pregnancies. For me, OPKs were the game changer, and I kept using them until I got a positive, i.e. test line darker than control line. That was how I found out I ovulated on day 21, not day 14!
DD1 conceived at 36, DD2 at 40.