My first 2 family when is the best time to refinance?

[Jon Ladas]

I closed on my first 2 family home less than a month ago in MA. It was owned by the same family for the last 40 years and needs some updates. I am living in the 1 bed unit (converting it to a 2 bed) and posted the vacancy for my 3 bed unit last week. I turned 27 back in September and have been working non stop to close on a multi for just over a year (long story they all kept falling through due to financing and what not). I was hoping to pay off PMI as soon as possible (I went the FHA route and put down 3.5%). I am updating my unit and will update the 2nd unit once I have the money to (doing every myself). How do I know when to refinance in hopes to pay off this PMI? Is it worth it to run the numbers after just updating my unit? Should I wait until I put significant work into the 2nd unit? Should I not even worry about paying PMI off ASAP and just collect rent? I don’t know if it helps to clarify that I am only living in it for a year (following FHA guidelines) and then I plan to rent out both units.