I would say once you have about a 6 month to a yearling (could be sooner if you have a good grower) that is eating well and is acclimated you can move them up to a larger enclosure. If this is your only snake I would also highly recommend saving up for a PVC enclosure. Night and day over any other setup short of a rack system. If however you have multiple snakes or are planning on having multiple snakes, I would highly recommend then to save up to either build your own or purchase a rebuilt rack system.