There’s also “if you have debt, here are some formulas to help you figure out how quickly to pay it off.”

Or “if you are debt free and want a car/a home/a loan, here are formulas to figure out how much to take on and how quickly to pay it off.”

And then there are formulas to tell you what to do with the extra $250/month you aren’t putting towards debt, because the answer isn’t “buy a cool shirt” or something. The assumption is that if you have money to put towards debt, you could also be putting it towards savings/money market accounts/investing/retirement/etc. Where should it go?