I've saved mine before too. It makes for a good lube, and it's kindda neat to see so much of your own cum in one place. I dunno, its just the kinky part of me that enjoyed it.

Anyway, if you want to save your cum (for whatever reason), you need to treat it like food, as in it will go bad if it is not refrigerated or frozen. In the fridge it will last several weeks before going bad, and in the freezer, it should last over a year. Although as several people have already noted, the texture won't be the same after thawing (becomes more watery and not as sticky), but you can definitely still recognize it as your cum (smells and tastes the same), and it makes for a great lube!

Fun saving it in the freezer for a while....

Why would you save it???
Probably for the same reason that you're registered on a website with the moniker, "JackinChat".
Can't judge people for swimming when you've got one foot in the pool already.