@Skarl
Sorry, I realize I never answered your question about my thoughts on IDR and
the WCI's advice on it. Well, I disagree with all of his points involving money since the math shows IDR can be of lower cost than aggressive repayment. I think the risk of an invested tax bomb fund is fairly low given a 20 year span, and as the math shows, the fund would only have to return about 2-3% per-annum to be effective (less the higher your debt). I also think the legislative risk is pretty darn low. While I understand his point about "sticking it the tax payer," if an option is readily available and advantageous, I don't see the shame in taking it.
That said, after giving it a lot of thought, I would still recommend aggressive repayment for most people, even big debtors. I agree with the WCI's points on the psychological effects of debt. Most people are risk averse and don't sit well with having a ton of debt and are not disciplined enough to build their tax bomb funds and trust in the long game. All this adds to a lot of extra stress on top of being a doctor. Most people also do not have the financial interest and knowledge to achieve the mathematical advantage of IDR nor the skills to determine if such an advantage exists. The biggest reason, however, is that most people will benefit from
living below their means, delaying gratification, and learning to save instead of spend (especially in tax-advantaged retirement accounts).
IMO, these are among the most important skills for everyone to have. The FIRE-eating asceticism camp is not for everyone, but I think most people would benefit tremendously from boot camping there for a few years to acquire these skills and make them habits. After that, 20% savings is a good thumb-rule that leaves plenty left to be enjoyed.