I started painting miniatures back in the late 80's, maybe early 90's. I have been through many a pot of paint in that time. Some finished completely, others that have gone hard and crusty and needed throwing. However I STILL have one pot of paint that I bought back in the early 90's that I still use today. Its a colour that doesn't get a lot of use but is great for tongues etc. Titillating Pink! Pot must be 25-30 years old yet just keeps hanging in there. Curious if any other "old timer painters' have a trusty old pot of paint??
None quite that old, most of the paint I have is about 8 years old right now. ...although I did have a pot of Chestnut Ink from 2002 on my shelf up until about a year ago, finally had to retire it after I used it all up!
I have several pots of older paint kicking around. I know I have several pots of bilious green and leprous brown somewhere as those were the primary colors for my first Tyranid army.
I still have a lot of old colours, nearly all of them still usable. The problem is the change of the names over time, but I've found nice tables for that: https://www.dakkadakka.com/wiki/en/Paint_Range_Compatibility_Chart https://becko.tabletop-minis.de/Tipps/Farbtabelle