I guess it depends on how extensive your renovation is but if its mostly cosmetic for 1-4 units it should be done in 3 months. 

Ideally, they would find new tenants and do some light renovations before renting it back out.

Had we used a licensed expert, we could have saved ourselves a lot of headache and money in renovations, that otherwise, could haver been negotiated to reflect more favorable terms for us.

I am a new Investor and I bought my first single family home a year ago on a loan given to me by a relative that was for the full price & some change to renovate.

You could also do a cash out refinance for the initial cash do the renovations and then do another cash out refinance after the renovations for the new ARV.In some cases investors do (2) cash out refinances - one to take enough for the renovations and then next for the new ARV and to pull out more cash for the next project at the higher ARV/LTV. 

I was intrigued by the size of the property, great location, and upside once I got the building performing and renovated.

Purchased the home cash, renovated it with cash, then did a cash out refinance.

I cashed in on a larger home, renovated, and move the family in. 

@Yumiko A.No it doesn't need to be rundown necessarily, but it's definitely going to be a home that requires pretty much a complete interior renovation.

@Steven M Herrick If you run the numbers based on After Repair Value ARV and how much you're buying for, renovation cost and what rents are going for, will it cash flow?