OB suggested Hysterectomy if periods >7 days... how do you count properly?

This feels like a pretty dumb question, but here goes: what counts as a day of a period? Is it only days requiring pad/tampons? Or any day you continue bleeding?

I'm 33, had 2 kids, 2 c-sections. Tried Mirena and Novasure for extreme bleeding after the 2nd kid. Novasure lessened the volume, for sure, but at my annual last week my OB was pretty shocked that I am continuing to have periods, let alone 5-7 day periods. He told me I'm borderline now for him recommending a hyst, but that if I bleed more than 7 days, I should do it.

Typically I wear tampons for 4-5 days, and then have some spotting or breakthrough that only gets worse with heavy exercise. This month I am on day 10 of "bleeding", but unsure if it qualifies as a day of my period. I'll obviously follow up with the doctor, but looking for opinions/experience.

I'm not sure I want/need a hysterectomy, but I am also investigating an abdominoplasty for diastasis from ribs to symphysis, so if I can combine the procedures I would very much like to.