Alloy stamp survival

Hi wonderful people of Ganoksin

I am wondering if it is just me, but my alloy stamps seem to blunt
very quickly… I guess I do stamp fairly hard, with the annealed
metal over a thick solid rubber base, but after about a year, the
numbers get very soft edges. If I stamp any softer, the numbers are
too shallow. I’m wondering if you good people have any suggestions
that might help me keep them nice and sharp for longer?

Cheers
Anna Williams