Transitioning FHA Loan to Conventional... Requirements?

[Abigail Okenge]

Hello, rookie here!

My husband and I currently live in a single family home outside of the city, but are wanting to rent out the SF and move into a duplex closer to the city/his school (he's a grad student). We are wanting to use an FHA loan to purchase the duplex and then house hack until we have enough cash on hand to do the same thing with another duplex (move out of duplex #1 & rent out both units, then move into duplex #2 using FHA loan to house hack). I haven't spoken to any lenders yet, but am wanting to ensure I have a decent understanding of FHA loans before moving forward...

If we purchase duplex #1 on an FHA loan, does it have to be our primary residence for a required length of time? Or, can we live there for 4-6 mo. before refinancing duplex #1 out to a conventional loan, then using an FHA loan on duplex #2? Hypothetically, can this process be continued indefinitely as long as we live in the property that we use to purchase with an FHA loan?

Any info would be GREATLY appreciated. Thank you!