// User can create many months $user->months // The Created month belongs to a user $month->user // The Created Month has many expenses $month->expenses // The Created expenses belongs to a month $expenses->month // User can create many shops $user->shops // The created shop belongs to a user $shop->user // The Created Shop has many lists $shop->lists // The list belongs to a shop/ $lists->shops // The shop has many items $shop->items // The items belong to a list. $item->shop }

i think months table is just an extra table, in expenses table you have date column from where you can months of specific year and those expenses directly belongs to user there is an extra link between user and expenses. so as for income table too.