When you've got a one shot alt for whatever reason. That you give it the same treatment as your main character that they eventually become characters in their own right. Usually even more detailed than your main.
Also when you end up going to several aesthetist visits because the hair reflects what happens too. I.e. your femme char put her ponytail down. So you run to nearest jandelaine and pay him the 2kgil for the change and pay him 2k gil again to change it back. When you have so many outfits for them they have at least 2 or more casual looks as well as ensembles for when they're working. So many variations to their outfits because they also change clothes too. Like you have three pairs of the normal lvl 5 caster sandals dyed differently and assigned to different outfits. Each set a part of their IC wardrobe. So they have some alt outfit wear if one of them's in for dry cleaning.
Also when you end up going to several aesthetist visits because the hair reflects what happens too. I.e. your femme char put her ponytail down. So you run to nearest jandelaine and pay him the 2kgil for the change and pay him 2k gil again to change it back. When you have so many outfits for them they have at least 2 or more casual looks as well as ensembles for when they're working. So many variations to their outfits because they also change clothes too. Like you have three pairs of the normal lvl 5 caster sandals dyed differently and assigned to different outfits. Each set a part of their IC wardrobe. So they have some alt outfit wear if one of them's in for dry cleaning.