I find old cans of Kodak developers at estate sales, etc. from time to time. They almost always are still viable. If there are no black flecks or overall brown tone amongst he sodium sulfite and carbonate etc white , you should be fine.
Sometimes with old developer powders you need to add like 5-10% onto the recommended development time.
Precise timing is something I fiddle with with every developer, old or new, so this causes me no grief.
I carefull open old cans from the bottom, so that they can make a nice display as well as being chemically useful to me.