It'll last a long time in freezer. Fresh frozen trim improves yield of bubble hash processes. Empty whole back into your ice water and no trichomse are lost. I regularly got 25% or more yield from fresh frozen trim that piled up over a year or so.
as far as breakdown of the thc potency... near freezing reduces loss significantly compared to storing at room temperature. And that's only 10-15% loss in first year at roughly room temp and 59-62% RH.
E.G.
if starting at 20% it's only down to 18% after a year. that's not a perceivable difference. freezing is even less of a difference.
Definitely look up frenchy videos. He covers the important parts -- even if you are not as anal as he is, it's good to know the cause/effect of choices. e.g. i didn't do 2 minute cycles because i didn't want to take 20 fucking wash cycles to finish, lol.
my pro tip -- have 2 batches of cold water and one of those portable washers to spin it, like in the frenchy video. The sooner you can start the next wash cycle, the faster you get done. Sieve and collect while 'next' cycle runs. can't do that with one batch of ice-water.