When do you consider it gone?

At what point do you consider AF to be gone?

I can't decide when AF is gone and I can start testing for ovulation. I dont know if I am regular as I'm just 2+ months off birth control so I want to test early to find a common trend over the months.

Currently, I am at the end of my period and I am having dark brown spotting, like old blood, and I don't need a tampon as it's not coming out of me. Sometimes when I wipe there may be something there but hardly ever.

When should I log my period as gone?