A general rule of thumb is 90 days at 90% occupied, but again, I would hold on to the seller finance as long as possible.If you are buying out the seller completely when you do eventually refi, yes, you will need to have some equity (whether that's your own, or another private investor / partner). 

I didn't know if it was some hard and fast rule that I hadn't heard of before.

I have posted a few times and I will admit that I have not read all the rules so I am going to post carefully.... hand one "flagged" in the past but no understanding as to why.I have been investing in RE for many years in a passive nature but just sold a couple of homes that were deprecated out and made some good money and thought.... if I had only had done that x 10 I would be set.I recently attended a $250 3 day event after attending a free 3 hour event. 

I follow exactly the rules that @Brandon Turner suggests which is the %70 rule or even %75 rule which is: Buying at %70 of the ARV - rehab costs.

@Garry DeFilippisIn my area I will not look at any property that doesn’t at least meet the 1% rule.  

However, as long as you aren't breaking the cardinal rule of overspending on your purchase, you "should" be fine.

Most times when you buy turnkey you are buying with negative equity because you're buying in areas where investors are taking over predominantly owner occupied areas for the 1% rule.

@Anand Sankhe I normally use a simple rule of thumb for this type of decision.

Also from my experience in SLC you the home owner are still responsible for the water and sewage (this may need to be included on your rents) I'm not sure what the rules are up there in cache county but keep that in mind as well.Currently being a landlord there are many things to keep in mind when investing in multifamily please feel free to reach out to me if you have additional questions or concerns.

If the potential tenants don't make that, they don't get the place.Another example is to have a clearly defined rule for previous evictions.I think if you clearly define your standards on these issues you will avoid tricky situations like this.Also, definitely do not put someone on the lease who isn't living there.Good luck!