Starting a complete record of expenses is the surest, fastest way for the average consumer to discover the damage of their impulsive behavior. I want to begin this section with two anecdotes.
First, in my early 20s, I knew a married couple working in engineering, one of whom claimed they lived on about $20,000 and saved the rest (>$100,000). This sounded low (two cars, plane tickets across the country several times a year, modest apartment, etc) so I mentioned it at dinner and her husband offered a revised estimate of their annual expenses - $40,000 a year. To reiterate, two intelligent engineers, earning more money than they needed, could not estimate their annual expenses to within a factor of two. I never looked at the books so I cannot tell you who was wrong by how much but I promise these two were in far better control of their spending than average and yet at least one of them clearly had not a clue how much money actually went out the door. Maybe they do not need complete accounting records, they can probably live their whole happy productive lives never knowing if they are saving 80% or 65% of their income. The point is without records, even if you are quite educated and responsible, you will never know.
The second anecdote is not a single story but a situation I have relived every time I successfully force someone to track their spending. My friend comes to me asking for help with their finances. They track everything for a week and become depressed as they see their money fly away so they stop tracking it. This is an ostrich solution to self-induced problems: "if I do not know how much I am fucking myself, I will not feel so bad about fucking myself." Months later they try again. This process repeats and eventually they find the discipline to track their spending (or they do not and I never talk to them about money again). Now together we have the opportunity to watch their spending patterns and the truly ludicrous behavior which led them to ask for help is unmasked. Invariably, over 50% of their expenses are not included in their initial estimate of what they spend because each item is "a great deal and really not that much money." They estimate their expenses based on the big stuff (transportation, insurance, utilities, housing, and groceries) but fail to account for consumer waste (truly frivolous spending), non-regular expenses ("I don't buy X every month so it doesn't count" does not apply if it is used to justify some new expense twice a week), and chronically underestimate the costs of eating in restaurants or drinking in bars.
Accounting is a beautiful illustration of the ease with which humans deceive themselves. If you really track your money, you will find the errors in your estimates as you discover how your behavior affects your bottom line. You need records to understand what you have done and to make improvements going forward. If you cannot identify where every single dollar that left your possession in the last two years went, you deserve no sympathy when you discover you have no money.