How old for reagents is “too old”?

[stkidsdoc]

Chemists out there, please advise. I have replaced most of my reagents over time as needed, with larger refill bottles from amazon. No expiration date on the bottles, but is there a time after which I shouldn’t trust them?
Realize I’ve had the base kit for 7 years now, but plenty of newer reagents (though all at least a year old now).
Thanks.

 

[mknauss]

If stored in climate controlled conditions, most will last 18 months or so. Some are more fickle than others.

We recommend getting refills from TFTestkits so you know the reagents are fresh to start with.