depends on your location, location, location and interest rate and life plans/circumstances but in some cases it make financial sense. but like
@pgg said, it's complicated math and there's more to it than rent > mortgage payment = profit.
if your house appreciates, as long as you are active duty the IRS rules allow you some benefits in regards to selling and not getting hit with capital gains. for most people, there's a residency requirement (must live there 2 out of 5 years I think) that when it expires and you sell you'll get hit with capital gains. so this means if you live there 2 years and move out, you can rent for 3 years before you will get hit (unless you move back into the house). being in the military stalls this countdown for up to 10 years. so, you can move out of a property for several years, sell, and still avoid capital gains. just a little military specific nugget for rental properties.
a few years ago I asked a few O6's what they'd do financially if they had to do it over again and several said they would have bought homes at each duty station to rent. obviously this is location dependent. we have a property in DC we rent, and our management company (which I highly recommend if you are renting finding a one stop full service management company) charges 8% of the monthly rent. For this, they keep track of all accounting for the property and arrange repairs and such for the tenant. it's been pretty hands free, and while we aren't making a killing per month, the property has appreciated steadily around 30k/year since we started renting. if we move back to DC-- no need to buy another place. if we don't-- we can sell and collect the capital gains free windfall (minus depreciation IRS gets back because the make it mandatory to claim on a rental... the bastards), or continue to rent it. it's nice to have the flexibility.
there are also other things like improvements vs repairs and depreciation and such but hopefully you can see it's not as simple as just buying/renting. I think that's why people just try to flip-- its' more straightforward. but just because it's complicated doesn't mean it's bad
we also own a vacation rental we (may) use a little here and there (IRS spies just kidding we never use it), which has a much higher ceiling for generating income but is to date much more of a headache (more frequent tenant turnover, advertising, etc).
-- your friendly neighborhood cavelord caveman
