I'm wondering about this also (I posted a Pros and Cons - spotty CD1 thread in TTC).
Last cycle, I was on clomid 50s CD 5-9. Went in for CD 14 u/s to check follie growth. Doc said "nothing going on on either side". I was crushed. I do remember at least one follie being 10 mm, and while I know that doesn't mean it was necessarily going to turn out to be a "good", dominant follie, it made me feel like if I'd had a bit more time, things might have been different.
Since last cycle I had three days of spotting before AF came full force (therefore RE counts CD1 as full force AF), I'm pretty sure I'll have the same thing this cycle (finished last of Provera today). I've decided that I'm going to count AF's first appearance, whether spotty or not, as MY CD1. I will start the clomid on CD 3, despite RE saying to do the Clomid 100s on CD 5-9. I will make my follie growth u/s appt for HIS version of CD14 (14 days after AF shows full force). This way I'm giving my follies some more time to grow, and jump starting the clomid in my system.
I'm not saying this is necessarily right for ANYONE else to do, as I've never really been given a concrete reason why REs differ between clomid on CD3-7 or CD 5-9. I'm sure some of it has to do with hyperstimulation or cyst worries. I feel comfortable doing this myself because if the 50s had NO effect according to RE, I am doubting that the 100s will be SO effective that they will cause me to hyperstim or get cysts.
If anyone can give me the medical reasons behind the CD5 vs CD3 rationale, or any other relevant information, I would greatly appreciate it.
ALSO!! Lol, I do not typically ovulate on my own, or at least I don't ovulate on my own before VERY late in my cycle. I can see how, if someone does typically O on their own, taking CD3-7 would move that O date a bit earlier. This could definitely affect your efforts, so its probably best to talk to your doc about the whys and hows.