I have been using a product called soup base, a concentrated paste that can be reconstituted into stock. It comes in all varieties (beef, veal, chicken, shrimp, etc.), and its quality far surpasses that of any canned stock I've ever purchased in a supermarket. It also lasts refrigerated for up to a year once opened. I typically cook only for myself, so it's impractical for me to make up a whole batch of different stocks to appease my varied appetite . . . I'd never use it all, & it would take up a lot of valuable refrigerator or freezer space.