At the lower price points, refrigerators are very common as you move up lesser so but still pretty common.

If all of you will be on the mortgage, then you could treat the investment as tenants-in-common, which means that you each own a specific fraction of the property and you split the revenue and expenses proportionately. 

Not implementing increases is one of the most common mistakes among new landlords.

@Darrel Hernandez This can be a common strategy to pull the equity out of the property through a HELOC versus a refinance.

But the common narration that "I'll just do a few flips/wholesales and boom I'll have enough money for a down payment for that xx unit building" is so much more complicated than advertised. 

While they can be developed in some areas, don't assume this strategy is common place and make sure to do some solid due diligence before purchasing.

It was definitely more common at one time to have sinks in bedrooms.

My lease says no more than 8 days every month because it's common for them to have someone over every weekend.You don't need to prove it.

We just found about it and I am little frustrated because now I have to coordinate times with the tenants.Is this a common practice for refinancing?

Beyond that, a lot of life is just common sense.