There are actually some benefits to getting 30 year mortgages and paying them off in 15. I like the flexibility of not HAVING to make that accelerated payment. Currently I am applying a pay down strategy to my largest rental loan, which also has one of the highest interest rates that I've got. I should have it paid off in 5 more years at the rate I'm going. Like financial people often advise about paying off credit card debt, I'm doing the same with my mortgages. That strategy is focusing on one and shoveling the money in. When this one is paid off, I'll take the thousands of dollars that I've been paying on it, and move to the next mortgage.
Although the interest rate on a 15 year is a wee bit lower, the commitment to pay the bank a lower monthly payment (and adding principle payments) might prove handy when getting more bank loans.
In case somebody doesn't know this strategy, I had this loan "recast", or "re-amortized" when I made a large principal reduction payment. For $250, a one time fee, the loan, which was set to pay off in about about 12 years with the payments and principal reduction payments I was making monthly, was recalculated to bring it back to the original pay off date, some 20+ years out. This lowered my monthly payment by about 1000 per month. (It was a big loan).
Since my goal is FI, I continue to contribute that same extra 1000, except now it goes 100% to principal. The loan mod department does this. This is the only way that I know to bring an existing monthly payment down without refinancing.