Fixed vs. Adjustable Mortgage - advice for a new-comer

[Alex Chin]

Good afternoon BP.

I am new to real estate but am interested in making my first purchase, hopefully before the end of the year. My plan is to purchase a small multi-family property, own and improve it for 5-7 years, and then transition it into a larger multi-family (i.e. - go from a du-plex to a 4-plex, etc.), rinse and repeat as often as possible for the next 15 years or so.

When I mentioned this plan to an investor, and later to a mortgage broker, they both said that I should at least look into taking out an adjustable rate mortgage, the investor said that he no longer even bothers with fixed rate mortgages for his long-term flips (what he called my plan).

I wanted to get other opinions as I obviously don't have much experience with mortgages. What questions should I be asking prospective lenders? What are some down-sides that I probably haven't thought of in taking out an ARM? What are your opinions on this plan?