Identify your use: topping/crumbs (crush) vs coating vs snack-style crunch (leave chunkier).
Replace pretzels using the 1:1 ratio by weight; for crumbs, crush to match the size of your original topping.
Adjust flavor: if the substitute is mild, add 1–2 pinches of salt per cup of crumbs (start small).
If you need pretzel-like browning (baked toppings), toast the crumbs 3–4 minutes at 425°F/220°C before using.
Bake or serve as directed, then taste and fine-tune with a tiny extra pinch of salt if needed.