I bury my fresh roots in the garden until i am ready to sell, i figure they lose about an ounce or 2 per 3 pounds. I have 6 p's in the ground now, sure i'll lose a quarter p but i will leave them there until i hear the asia buyer is in town around thanksgiving~ then I will dig em up and have fresh roots to sell. they usually bring a premium that time of year which makes up for the lost weight
I never hold roots from year to year, not fresh or dry after all it isn't gold so no need to hoard it. The way i look at it if you have roots that were dug 2,3,4 years ago you are losing money waiting for a target price that may never come, you also risk theft, damage, and/or buyer rejection.