Rehabbing rental properties

[Craig R Marett II]

I’m a newbie looking into rental properties and flips in my area. I really like the brrrr strategy but guess I don’t fully understand it. If you are to rehab the property first, can you only do this with properties that don’t have existing tenants? How do you rehab with existing tenants? I’m assuming the building must be unoccupied to execute this strategy? Or if a deal is too good to pass then rehab available units and rehab others in between vacancies and then refinance ?