The naturally porous surface of stone needs to be regularly sealed to repel water-and oil-based stains. Soapstone is soft and most prone to chipping. Professionals can often polish small scratches and chips from your countertop. Cleaning and polishing can also restore the shine back to stone which has become dull and hazy. If a solid stone surface cracks, the entire countertop will need to be replaced.
If you just bought a manual miter box, a simple modification will extend its useful service life. Insert and fasten a piece of 1x stock to the inside bottom of the box. The saw blade will then cut into the false bottom, without damaging the miter box itself. Occasionally move the wood back and forth, or turn it over, to spread out the wear. When badly cut up, just replace the piece.