Has anyone paid attention to implantation bleeding?

I rarely spot outside my designated period week...and by rarely, I mean not one single time in over 5 years. I'm not under any absurd stress or anything that could cause spotting. We're TTC baby #1, and I'm super new to all of this. I'm about 9 DPO and, while I'm usually cramping like crazy right now, the only symptom I have are sore breasts (as in owwwwwowowow all the time). I made the mistake of testing way too early and of course got the BFN, but that was my fault for testing 2 DPO (silly me for miscalculating in my excitement!).

Anyway, what are your experiences with implantation bleeding? How many days DPO? Anxiously waiting until I can accurately test!