It’s way bigger than you might think. Consider this: You’re buying a $200,000 home in the Billings, Montana vicinity. Assume your taxes are about 1.2% of the purchase price ($2,400/year, which is probably a little high) & your insurance is about 0.5% of your purchase price (about $600/year, which might be a little slim, depending on the age). Assuming an FHA loan with 3.5% down (the minimum) & rates hovering near 4.75% for a 30 year fixed mortgage, your PITI would be $1,446/month. If rates were 5.75% like they were a year or two ago & everything else the exact same, your PITI would end up being $1,567. WOW! Over $121/month savings. That means you can buy about $24,000 more house for about the same payment! Holy Buckets, Batman!