If you’re like me and lack space to hold onto things that you may need in the future then vacuum seal bags are a blessing. It seals really flat so then you take up much less space than you would have if it was put away in a box/blackbag.
After every clear out for the past few years I’ve stored away all the items of my kids clothing in size order and clearly labelled it. So then when it’s time to take out the size, it’s simplified. I’ve even done it for my maternity clothes and my parents even vacuum sealed my wedding dress! So pretty much if you really want to you seal anything.