I'm slowly trying to break through to a couple I know, who are good friends, who are convinced paying the mortgage off RIGHT NOW is the best way to go. I put together a little story, deliberately trying to keep it simple. How could I improve it?

One person, we'll call him Ross, decided he wanted to pay off his mortgage as quickly as possible. His normal payment was $1,000, and he has another $1,500 per month he could put toward the principle. This will get his mortgage paid off in about 8 years.

Another person, we'll call him Mr. White, also wanted to pay off his mortgage as quickly as possible. His normal payment was $1,000, and he also had another $1,500, but instead of sending it to the bank, he put it in a safe investment that he maintained control of. Because the interest on this investment is the same as his mortgage rate, he will have enough to pay off his mortgage in 8 years. His plan is to pay the mortgage in one lump sum when his invested balance equals the remaining principle balance on the mortgage.

If Ross suffers a job loss in year 5, he still has a mortgage payment due next month. He has no "mortgage repayment fund" and the bank will offer him no leniency because of his accelerated payments over the last 5 years.

If Mr. White suffers a job loss in year 5, he still has a mortgage payment due next month, but he has 5 years worth of mortgage payments saved up. He can weather a much longer period of unemployment than Ross can.