Well you don't want something like a beagle that has a penetrating bark.

MFs are priced too high in my area, exit strategy is limited to cheapskate, low-ball investors like yours truly, and I don't like "my neighbor's dog barks all night" phone calls.While MFs have their place, there is always a strong demand for a house with a yard, especially for people with pets. 

We haven't even mentioned bed bugs, roaches, rodents, noise/disturbances/dogs barking, people who aren't residents dumping couches in your trash bin, litter, animal poop...Multi-fam can be profitable, but you run it like a business, not a "Mom and Pop" shop. 

Did it dig up the yard and bark at the neighbors all day?

Things like, how furry (i.e. sheddy), does it bark, does it tear things up, how well behaved, etc.You don't have to set expectations for potential tenants, only for the tenants you place in there.

Some scratch doors or bark incessantly.

I stopped by some of the old neighbors only to find out that the new tenants are holding the neighborhood hostage by calling the police on the older gentleman next door because of his dogs barking.

You will hear their dogs barking at 2 am, at 3 am, at 4 am, at 5 am.   

But it's also worrisome to have an unspecified dog I never met near wood floors, new laminate, possibly barking, and disturbing my second tenant. 

Or listen in on a conference call with several dogs barking/babies crying because everyone is at home.Commercial real estate is evolving for sure but I think that just means opportunity.