Preheat the oven to 350°F.
(If making your own crumbs, the number of full sheets will depend on the brand, since manufacturers have changed their size and weights.) Break apart the graham cracker sheets into a food processor or blender. Pulse until a fine, crumbly mixture forms (the consistency of coarse sand.) You should have 1½ cups of crumbs. Pulse more sheets, if necessary.
In a medium bowl, combine the graham cracker crumbs, butter, and sugar until well combined.
Pour the crumb mixture into a 9-inch pie pan. Starting with your hands, apply gentle pressure until the crumbs aren't loose anymore. Then using a small flat-bottomed measuring cup, pack the crumbs in more (but not too hard or your crust will be dense), smoothing out the surface and to set the shape. The crust needs to be compact but not so tight that it's hard after baking. Finally, slide a spoon around where the bottom and sides meet, keeping it rounded so it all stays connected and won't crumble when you go to slice it.
Bake for 10 minutes, then let cool completely.
Use right away for your favorite pies or store for later.
