I've done a year with a normal NET liquid. After getting it out of the freezer and letting it breathe and the normal aging process, it was as fresh as my normal liquids. The aging process didn't start until I took the cap off.
There was no noticeable difference between my regular, non-freezer stored and the year old freezer stored liquid. No difference in taste, no difference in color. I only vape one flavor of liquid. Day in, day out. I know what it is supposed to taste like.
One year and a 30ml bottle, right into the freezer after getting it out of the mailbox.