Come on, that's a stupid question! Realistically, how many days could you actually eat the SAME sandwich? Unless you take *very* small bites, it would be gone after just a few meals. And even if you DID take very small bites, you'd have maybe a week at best before it started getting moldy. And even if you continued to eat the moldy sandwich, there's will come a point that the mold/non-mold ratio would no longer allow it to be considered the "same" sandwich (although philosophers have argued for years about that exact ratio).