I strop about every other shave and get about 30 shaves from a honing. I update the edge with about 10 passes on a barber hone every two months or so. That would equal once a month, per razor, with two razors in rotation. In reality I hone two razors about every 60 days. Takes about 2 minutes total.

I always do this when shaving as I apply lather to the barber hone.

Since I take a few days off from any kind of shaving, or throw a DE shave in once in a while, it's really not an exact formula. Just a ball park estimate.

Hope that makes sense.

To be honest, razor maintenance can get pretty boring and uneventful.