<prompt> Human: I have the classic 30-year fixed mortgage at 3.75. My plan is to pay the MINIMUM each month and put NO additional payments towards my principal. All extra money I have goes into the market in index funds, target retirement funds, blue chip stocks, and SP 500. Contrary to popular advice, all bonuses or extra money goes into the market, no extra payments to chip away at my mortgage. Instead, Ill wait until I have enough money to pay it all off in one lump sum, hopefully within 10 years.Reasoning: Paying extra money towards the principal will reduce the number of payments I have to make. So if I get a 10k bonus and put it all towards the principal, Ill hypothetically reduce the number of payments from 360 payments 30 year mortgage to 348 payments. Thats great and Ill have a mortgage for 29 years instead of 30 years. But what if I took the 10k and invested it in the market for 10 years. That 10k could potentially become 15k. Why put money into a mortgage if that money could grow in the market instead? What if the market crashes?Im sure many people will ask this question. I see it as a low risk because the market has always bounced back. Even during the worst recession of our generation in 2008, people who left their money in the SP 500 would have gotten their money back and more. So if my goal is to pay it off in 10 years, and the market crashes at the 9th year, I still have 21 more years for my money to recover until my 30 year mortgage ends. Im sure it will recover in 6-8 years, so I end up paying off my mortgage in 20 years instead of 10.Background: Investing for a decade now with no debt and my net worth is equal to my mortgage. But it includes my 401k and IRA, which I cannot liquidate in order to pay off my mortgage. Wouldnt make sense.TLDR: Do not put extra money towards mortgage principal. Put all money towards stock market and pay off mortgage in one lump sum.  <response>: I mean from a purely financial standpoint. You payoff the mortgage over 30 years and always leave the money in the market since the real return would be best there. 