I think this is How to manage money, how to plan for life, and how to become rich in the future without doing anything complicated to soften the day-to-day strain on your finances. An addition from me regarding the above, one of which is the implementation of time management methods is to set personal rules and develop them. Maybe it's not a rule, but a ban on shopping or buying things that are not important and trying to avoid credit in buying something.
If someone wants to manage finances in his life, then what needs to be considered is how he manages his time in making money and also how he spends money when he already knows how much money he can make in each month. Even though what you say is also true in trying to avoid credit or loans of any kind in order to buy something that is generally not very important for him to have