The general rule for me is 60-90 days assuming your BAC water is also not over 90 days. Beyond 90 days is what the science shows as compromised.
Lets say your bac water was used 30 days. You recon some Reta. So 60 days into your Reta vial the that bac water is now 90 days since it was first punctured. That would be my cutoff and I'd have to throw out the remaining Reta in the vial.
There are exceptions to this such as Tesa. That is honestly only good for like 7-10 days. NAD+ that is unbuffered is really only good for 2 maybe 3 weeks. It degrades fast. Not really a safety issue but a product quality issue. The buffered versions of NAD+ appear to last around 4 weeks before they begin to degrade.
