I know this is going to vary so much from person to person, but is there a general rule of thumb for when debt becomes “crushing”? Is taking $80K in loans, while having a free and comparable option available, worth it?
You're right, it depends on the person. Is 80k a lot most students and residents, sure. Is it a lot for most attending? Probably manageable, but more annoying than annoying. Is it for Jeff Bezos or Bill gates? No, not at all.
Is this 80k total, or 80k/year?
If its 80k total, simply ask yourself if that would be crushing to you consider the average is like 200-250k I believe. Only you can answer that question.
If it's 80k/year, then go where it is free.
Now, if you have a comparable option, as you put it, that is free, then why is this question even being asked? The only time this question should be considered is if they're not comparable, but how much is the 80k truly worth in the difference in education and opportunity provided.