I was looking at my collection history on Pinside and my current collection, I have been in the hobby ~14 years and have owned 20 pins (TNA on order will be number 21).
I’ve owned the most 10 pins at one time and one pin I have bought twice (SM).
I’m almost at an equilibrium with 11 sold and 10 owned once I get TNA so will have kept almost half the pins that have crossed my door.
Can post your total number and most owed at one time.