I'm curious, is that for racing or just in general? My personal bashing guideline (I dont race) has become relegating a pack to light duty use at about 10mOhm and then retiring it completely somewhere around 16-18mOhm.
I do that for performance reasons, the battery tends to fade and loss of capacity begins there plus the pack starts to take longer to charge, my absolute cutoff is 15mΩ: