How much debt is too much debt when deciding on which college to attend?

I think it varies a lot based on what you want to study. If you're going into petroleum engineering and can expect to land a starting salary of like $90k + benefits, you can probably afford to float a bit more debt than if you're going to study art history and can expect to land a starting salary of 1-2x minimum wage, then probably avoid taking on a lot of debt because you will literally never crawl out from under it once interest starts piling on.

It also varies on comfort - I specifically went to the cheapest state school I got in to, which cost like 4x less than other options available, so that I could graduate with basically zero debt (working during school and during the summer, and a couple of scholarships). Even at a state school with work now it might not be possible to graduate with zero debt though 'cus costs are way higher.

Below follows a bit of a rant on debt:

Debt, especially at higher interest rates, is no joke. Look at some amortization tables and costs to get an idea. Say you go to Northwestern University (70k year including tuition/books/room/board/etc), and take out a loan to do so (280k), and let's assume the interest rate doesn't go too much higher (but they are rising) at about 5%.

If you wanna pay that off in 10 years (http://www.amortization-calc.com/loan-calculator/), you'd be having to make a payment of ~$2900/month for 10 years. If you only make $50k/year out of Uni, that would not strictly speaking be possible without living in near poverty, so you'd probably end up having to stretch that out to 20 or 30 years (still a $1500/month payment). If you account for the fact that the $18,000-$25,000/year you'd be paying for loans is money you wouldn't be investing at ~7% gains per year, you will be out ~$450k in 10 years, or ~$1.2m in 30 years (https://www.bankrate.com/calculators/retirement/investment-goal-calculator.aspx).

Then you have to weigh that against the probability that a college education at a specific expensive school will net you more than ~$1m additional in 30 years or whatever. If you can expect a salary of $30k/year higher, then maybe. If not.... I dunno.

At least those are the similar sorts of pessimistic numbers I ran before going into college.

Of course bear in mind that I was also an idiot and had no idea how much big tech companies pay on the coasts - I assumed I would be making literally 4 times less money per year than I am now. So the probability statement I wrote out was probably somewhat wrong. So maybe if a Harvard whatever degree gets you into a cushy management position in a company with a good career track, maybe you still come out ahead? I don't know.