Wear is application-related.
If, for example, paper, cardboard, fabrics or foils are cut directly, the wear tends to be higher because the mat is permanently cut into. The adhesion is also lost more quickly due to the cuts.
If only adhesive foils are used, the wear is lower because there is still a protective paper between the foil to be cut and the mat. So instead of cutting into the mat, you cut into the protective paper of the adhesive.
If there is dirt on the mat that leads to poorer adhesion, this can be removed with a wet cloth.

From time to time you have to buy a new mat because you can't do any plotting without cutting the mat.

Yes, after some time the mat has too many cuts and needs to be replaced as it no longer adheres well enough. It is almost impossible to plot on it without producing small cuts.