Tax implications of turning primary residences into rentals?

[Ethan Fischer]

My wife and I are looking to buy our third property. Our first is a STR in a great market and is starting to cashflow. We bought it as our first property before buying our primary residence. We now have a primary residence as a house hack with a STR in-law suite that has done well enough to cover most of our mortgage. We are looking to rinse and repeat, and buy a third property that will be our next primary residence with again a STR in-law apartment in the house. We've lived in our current house long enough that I don't think we risk anything with our mortgage in turning our home into a long term rental when we move out and we can set aside the discussion around challenges with our debt to income ratio, the down payment advantages, and if the numbers work on the specific property. From what I can gather, there are lots of opinions on whether it's a good idea or bad idea to turn your current home into a rental property. I want to avoid that discussion.

What I am interested to learn is if there are any tax disadvantages or a blind spot that I am not accounting for in the plan to buy a house hack, move out and turn it into a rental, then buy the next house hack? 

I've learned that you get a tax exemption for capital gains up to $500k for our joint return when you sell a primary residence. In this case, we wouldn't be realizing the gains from the sale until much later. I believe we could move back into a property for 2 years out of the last 5 before selling it to get that same advantage. Is there something else I am missing? Is it foolish to lose out on the tax exemption and take the money now (maybe in opportunity cost) by leaving the property as is and keeping it as a rental, as long as it cash flows and isn't a headache? 

I haven't seen much on this topic. Curious if anyone has any insight. 

Thanks!