if you do "Pike" or "Dike" house (depending rhe version of your game) before, then he will help old gaffer to set up the shop and will sell his whole inventory

if you do gaffers shop before, the he will set up the shop himself and injure his back during the process

there is some other mini quests like that, for exemple, later in the game there will be a water shop, I think the name is Suzy and she will ask you if you want to rename it and you will have many choices, depending of the choice the invzntory of the water shop will be different!

also, there is something with Claude, depending of what time of the day you go, you will earn a different reward

you can either have a candy or a soap the candy is a quest item, if you trade it enough times you will have the best gem in the game

but you will have 2 occasion to get the candy, if you did not get it at claude's house, you will be able to get it in the next village at momo's house

but even there, it is missable, you could choose a weapon for goro instead

but anyway, you do not need 2 candy, one will end up rotting in your inventory storage