I sort of put homemade bread crumbs and croutons in the same category: so easy, so flavorful, so fresh and so cheap, it's a crime to spend money on the over processed, under flavored, preservative laden versions you can buy in the grocery store.
I often have need for Panko bread crumbs, and will avoid a recipe that calls for them, simply because I do not want to pay money for the aforementioned versions available to me in the local market. I decided to try making my own. The good news is it was so easy, I can't believe I didn't try it sooner.
Any day old bread will work. If you make your own bread, this is a great use for any that goes into day two and remains unconsumed. Even cheap, store bought bread will work, but I recommend you buy the bread baked in the market bakery vs. the commercially baked bread sitting on the shelves. If you look for the day old bread, it's even better (read cheaper). One loaf of bread will make a lot of bread crumbs.
I used whole wheat hoagie rolls for my bread crumbs, but you can use anything you like. I did not season mine prior to baking, either. If you like seasoned bread crumbs, season away.
Simply cut your bread into pieces that will easily feed through the hopper of your food processor. Soft bread tends to struggle a bit going through the shredding disk, so if your bread is soft, let it sit out for a few hours, so it dries a bit. Fit your food processor with the large shredding disk and feed the bread pieces through the hopper.
Heat oven to 300 degrees. Spread bread crumbs onto a baking sheet, in a thin, even layer. Bake until dry, 10-15 minutes. You may need to go a little longer, depending upon how many bread crumbs you are baking at one time.
When sufficiently dry, remove from oven, and allow to cool on the baking sheet for an hour or more. This will allow the crumbs to dry further. When fully dry, transfer to an air tight storage container, and keep up to six months.