whenever making an important decision to consider first and carefully,
when we are careless then the consequence we have to accept is losing money
I think most people miss something that is invaluable when making decisions which is the cost of opportunty, implicitly time and mental resources.
So adding to your conclusion @Inspiron14: "When we are careless the consequence we have to accept is losing money, time and mental resources."
That is why planning is very important in pretty much everything we do. Many think that it is boring and everything should be done spontaneous. While spontaneity certainly has its time and place, planning can save us so many resources that you can't argue against it. I mean there are people who "bury" themselves in monotonous tasks for so long that it becomes so hard for them to make and adhere to another plan. But that is also due to a lack of initial planning.
So plan what you're going to do carefully and tediously. You're not going to regret it. Maybe you have money problems --> ask yourself what can I do to get out of the "hole"? What are your options right now? What and how are you going to do? etc."