First of all, income is influenced by expenses: it is difficult to spend more money than you earned.
Then needs influence.
Basic: food (what kind of food you can buy, what is suitable, are there any health restrictions), water, a roof over your head (and hence the climate – the more severe it is, the more housing costs), clothing.
It is also important here, whose needs a person satisfies, only his own, or also contains a child, an old man, a wife on maternity leave.
Basic needs also include health, which means spending on medicines, doctors and sports. They can be very different depending on the need and availability.
Activity-related needs also affect the cost structure. Do I need to follow the dress code and how much does it cost, do I need to buy tools, materials, literature on my own. Even the road to work can make a big difference.
Affect the cost structure and spending needs for prestige. Not just a smartphone, but certainly an iPhone of the latest model, otherwise it’s a shame. Not just registering a marriage, but also arranging a wedding for the whole village so that they will remember for many years.
And of course, the structure of expenses is influenced by a person’s ideas about how to spend money. Does he think that a suit worth a month’s wages is too expensive (and will not buy), or that it should be (and will buy then). Does he think that meat should be on the table every day, or only on holidays? Does he think that all acquaintances should be invited to the holiday, or just the closest friends are enough.