衣替え（ころもがえ) on 1 IV and I X: Change clothes from summer to winter (and vice-versa). During this time, also air the 着物 for a day hanging.
たとう紙（し）, acid-free paper encasing for 着物. To prevent light; but also you can label them.
They are 88 × 36 cm, but there are also small (half-size) たとう紙!
When folding the 着物, these can also be spread on the floor to prevent dust from getting into it.
For folding, there are actually different ways for nagajuban, 着物 and haori
Silk 着物 are not prone to be eaten by bugs, but wool is. So use a repellant (camphor blocks, bochu koh; wrap these in paper so they don't come in contact with the silk) to dispel them;
They need air!
Store them folded
To transport, a ふろしき is not a bad idea, folding the 着物 around all the other things you'll wear.