When is it ok to move crestie to 18x18x24?

[chibicricket]

Currently Loki, my 7 month old crested gecko, is in an 12x12x18 bioactive exo terra, and I've been building up a 18x18x24. When would be ok to move him over to the bigger enclosure? He was so tiny when I got him, but now he seems like he's growing too big for his enclosure pretty quickly since he hit the 6 month mark.

 

[acpart]

If you have the feeling that he's outgrowing his current enclosure, feel free to move him. I put my first crested gecko, only about a month old, into a 12x12x18. 15 1/2 years later, he's very happy in his 18x18x24.

Aliza