Often carpenters will make quick work of cutting fiberboard sheathing by making their cut marks with a chalkline instead of a carpenter's pencil. Hook the end of the chalkline on one end, hold down the other end, and snap to make the line. The same idea can be used on other sheet material.
Here’s a way to get more life out of an old hacksaw blade. Mount it on the side edge of your workbench with about half the width of the teeth sticking up over the top surface. This will give you a handy cutting tool. Make sure that the location of this cutter is both easily accessible as well as away from frequent brush up traffic.