Mat and Material Combinations

How long will the mat last?

If the blade cuts through the mat, can tape, etc., be attached to the back so the mat can be reused?

Can rough material be cut?

Can different types of material be attached to the same mat for cutting?

Can multiple sheets of material be overlapped and attached to the mat?　

About Blade Extension, Cutting Pressure and Mat

I find some scratches outside the grid area (the attaching area) on the mat. Why is such a scratch attached on the mat?