One of my frustrations with the game is that the armor stops at level 18. I teach 4th grade and have my students all day and all year. Last year we went all the way to level 100 and post level 25ish the students were desperate for something to do with their excess GP. I started converting it to XP but I lamented that the thrill of getting new armor was gone.
As I've been pondering how to fix this (see my post about new armor ideas and incorporating races into the game https://help.classcraft.com/hc/en-us/community/posts/360018567533-New-Armor-Suggestion?page=1#community_comment_360002619694 ) I think I may have found a solution to this problem until they apply the above suggestion.
Once the player has trained every pet for a class, I will let them change to a different class. The key to this working and creating a potentially new set of armor is when you change their class, reset their GP to zero. This makes it so they have to level up 18-25 more times in order to get the new class armor. Once again they have the thrill of discovering and equipping new armor. Also you can only allow class changes via this method or it won't work. Meaning they are locked into a class until they train all the pets.
Once they have successfully trained every pet in the new class, rinse and repeat. Thus you can get all the way to level 75 before you have "done it all." At that point it is a race to level 100 and that close to the end, the thrill is in being first.
Let me know what you think!