What I find strange is that 11 years ago when I got pregnant with my oldest, I would have tossed a super faint positive and figured it was negative. Same thing with #2. But with my 3rd child, I started testing like crazy at 8 dpo until the lines got darker. Even when I went to the doc and the loser told me my blood test was negative (although she was wrong.....the lab messed up my results). After the doc got super rude, including having the nerve to ask WHY I'd taken so many tests, I went home and took 5 more! FR, ic, and digi's....all were positive!! To answer your question, 1 back in the day. Now if I see a faint line, testing will be a daily thing until a very obvious positive shows or until I get a posiyive digi!