I've had the Go crank for years. Mats are very important and very consumable. A worn mat will not allow the blades to cut the fabric through in spots. The mat will not heal itself. When you buy a die buy two mats. I think of the mat like a rotary blade. Both need replacing as soon as skips occur. I keep a good supply of mats on hand because I use my Go for 99% of the quilts I make. I buy a die to fit the size or adapt the size to fit the die.