The only strops I ever nicked were 2 DubleDuks back in the 1960s and they have been sanded to the point where they are quite useable.. Since then I have been amazingly fortunate using the counting method just as a musician would count time while playing an instrument.
I have about 12 hanging strops and no nicks in about 40 years. Counting works for me. I have had many close calls but counting has allowed me to stop before the edge hits the leather. Again, I have been very fortunate............ 1and2and3and4........signed, LUCKY:)