For a daily use straight razor, about once a season or twice a year. Remember that you keep a razor sharp by using the pasted strop and having a good maintenan

For a daily use straight razor, about once a season or twice a year. Remember that you keep a razor sharp by using the pasted strop and having a good maintenance routine. After a while the cutting edge becomes more convex, which is where the stone is needed to straighten out. A coticule is flattened on every use, because you rub a smaller stone on it to create the milky suspension that will do the actual abrading. I've had the same stone for 20 years.