Every year, Social Security is eligible for a COLA. When inflation remains flat, Social Security benefits remain flat. When there's a decrease in inflation from one year to the next, Social Security benefits also remain flat.

When September's CPI-W data becomes available in October, the SSA will compare the third-quarter average to the same period a year ago. Any year-over-year increase becomes the COLA. For example, if the data shows that prices have gone up an average of 2.5% over the course of those three months, then retirees would be in line for a 2.5% raise.

Retired workers will collect an average Social Security check of $2,005, enough to live well in these three expat havens.