Kids learn everything so much quicker than most adults! Why not take that opportunity to teach them how to avoid chaos and clutter from the beginning!?
Teach kids early about putting things away and storing things relatively neatly. Teach them to donate or sell their old toys, books, clothes, etc. You may even want to buy them a bin or storage cabinet and help them choose how to label it!
If they get started early, they will thank you later in life! Of course, all of this will come much easier if we model clutter avoidance for them as well! ;-)