I need more Lego rubber bands.

I've been rebuilding some of my older Titan sets, ranging through the various Rahi I now own. But as I pulled out rubber bands, they kept breaking. And I can understand why; they're roughly ten years old and have had a lot of use. But the thing is, how do I replace them? I could go order them online I suppose from some Lego enthusiast, but even then the types I'm looking for are gonna be a decade old, and while plastic parts don't degrade over time, I've found that rubber bands do.

So, what would be the best way to find replacements or substitutes for rubber bands for Lego sets like the Rahi? Because, as cool as functional sets are, they don't work as well without rubber band elastic action.