Buy a gallon or more, and immediately break it down into new quart cans. Seal them tightly. Air space in a partial can is what makes paint go stale- - - - -the less air, the longer the shelf life will be. Getting the entire batch mixed at one time will minimize the chance of not getting a good color match with smaller quantities mixed in separate batches.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!