If your dates are firm, soak them in warm water for 5 minutes, then drain well. Soft dates blend better and keep bites tender.
In a food processor, add oats and dates. Pulse until the mixture looks like coarse crumbs with small flecks; don't overdo it—we want texture.
Add peanut or seed butter, honey, vanilla, cinnamon, salt, and chia/flax. Pulse until the dough starts clumping. If it's dry or sandy, add water (or milk) 1 teaspoon at a time.
Stir in chocolate chips and any optional add-ins by hand. This keeps chips from melting or pulverizing.
Scoop about 1 tablespoon per bite and roll into 18–22 balls. If sticky, lightly wet your palms or chill the dough for 10 minutes first.
Place on a parchment-lined tray and refrigerate for 20–30 minutes. They'll firm up and hold shape like champs.
For kids 30–60 minutes pre-run, pack 1–2 bites. For longer runs or older kids, 2–3 bites is the sweet spot.