My lines were clear, but still fainter than I wanted until my test yesterday (13th) that one was as solid and strong as the control line. AF would have been due on the 8th or 9th so it took a few days after that to get really strong (picture shows tests on the 9th, 10th, and 13th). Yesterday was 17 DPO for me, assuming I ovulated when I think I did.
The test I took on the 7th was super faint, but that was still a little early I guess.
I think I'm done testing now, I don't want to drive myself crazy.