At 7 years the properties were paid for and I was making more money in a day (annualized) than I did in a month when I was employed and retiring much earlier than most even consider.

This would include any Money for college funds, retirement, ext.

The seller said that all debt would be retired via the purchase price.

Be certain to have your lawyer draw-up a formal contract as would be the case with any private lender.I would also ensure that you make a "principal" payment into a holding account (high interest, GIC, money market) each month so you have the necessary cash on hand to retire the balance of the balloon loan when you refinance to a conventional mortgage in 3-5 years ... unless the value of house appreciates substantially in that time period, you will not be able to place a mortgage for your entire purchase price.

I can't make this a full time job as I already have one and this is for my retirement funds).

I just retired from the military in December 2012, got my real estate license and I'm now a full time investor.

I'm retired Air Force and currently employed as a Project Manger.

What is your opinion (or anyone else's) on using retirement funds to pay down current debt (student loans).

If we could hold out until it was paid off then live there to retire would be one thing but seeing my wife has a brother, it would have to be split 50/50.

They may be retiring, they maybe be selling to move up to a larger property, they may have held the property long enough that their IRR has fallen and they want to invest elsewhere...