I use the 7 day CIDR with GNRH and Lut and then breed on observed heats. I hear that the results are better with 7&7, but that additional trip through the chute keeps me from using it.
Most years I get good results, but occasionally get a non-responder. Usually in heat 2.5 to 3 days after pulling CIDR and giving Lut. Two years ago, I had one that did not show any signs of heat and we did not do the timed AI. She was then in heat 8 days after the CIDR pull and Lut, well beyond the time expected. She settled and calved from that breeding date. Not sure how that happened. But would welcome comments. It was like there was no response to the CIDR and lut.
Back this last December when we had the deep freeze and the very high winds, we pulled CIDR's on December 20 at 7:30 am. We bred based on observed heats on Dec 22 pm. One cow was just starting to come into heat. Since we were going to have 50 mph wind and 15 degrees the next morning and we breed in an open shed, we breed her early with the others. Estrotect sticker was completely rubbed the next morning. Have not seen any signs of heat since, so hoping she settled. She is a big girl - 8 frame and wide and very gentle/stubborn. Hard to get down the 28" alley, so we bred her tied with a halter at the entrance to the alley. My daughter is short and usually stands on something to breed that one. She said that she was a little short of getting completely through the cervix. Maybe that worked in our favor with the timing of breeding vs heat.
Issue I have with CIDR's is that sometimes I don't see much riding. I will sometimes see subtle signs of heat, but stickers are not rubbed at all. Maybe just a bull calf following trying to ride, or the cow acting strange. If it is time for them to be in heat and I see just those subtle signs, we breed them and they usually settle. But a lot easier if there is a lot of riding going on. I have just a few cows. I think it is harder to detect the heat with just a few.