Lab reports should be current. I'd say anything older than 12 months is a red flag. Vape liquids can change over time, and manufacturers may switch suppliers for ingredients. A recent report gives you confidence that the product hasn't been silently altered.

If a supplier hands you a report from two years ago, ask for an updated one. If they can't provide it, that's a sign they might not be keeping tabs on their own products—or worse, they're hiding something.