I have stored a few this way for 10+ years, without damage. I do take them out of the bags a couple times a year, fluff them up, let them breath for a bit. I tend to rotate the quilts we use, the winter quilt, spring/summer, and fall. So they get their time out of the bags and through the year gifting/donating occasions come up like weddings, anniversaries, birthdays, fundraisers, -- reasons to get them out & share/pass them on. But, I do love those space bags! And I do have a couple quilts that only come out for a few days each year, a fluff/rest then back in the bag. They've not suffered or show any sign of batting breakdown or permanent creases. I do fold them different each time they come out