How long should test kits last (shelf life)

[chaostactics]

I'm guessing people who test their water as frequently as they should i.e. not me probably run through their test kits before the expire.

However, I was a bit dissatisfied to learn that a Tropic Marin test kit I bought at the very end of December 2019 had already expired in October 2020.

I'm guessing manufacturers pad their expiration dates a little bit so the test kit is probably good maybe for a couple of months past this expiration but I was wondering is it usual to receive a test kit from a well known and respected vendor and have it expire in less than a year?

 

[Biglew11]

Most test kits have about a one year expiration from date of manufactur. I haven't tested how accurate they are past this date, but some may be ok as long has the powders stay dry and the liquids haven't evaporated at all.