with DS1, I tested exactly a week late. I had the perfect 28 day cycle before I became pregnant with him, and kind of knew I was pregnant two weeks before I tested. I just was in denial (I was 19 y/o).
with DS2, I tested at 11 days late. I had a cycle that was anywhere from 29-40 days, and in the past I'd test, and test, and it'd stress me out, making my period later. Just 6 months before finding out, I had gone 59 days without a period, so I didn't want to get my hopes up. But I was a smoker, and I had a feeling something was off, so I bought a test, took it that evening and sure enough, within seconds it showed up that I was pregnant.