Is there a rule of thumb on how much to net per unit?

[Michael Kohlhoff]

I currently own a 4plex in central WA state and a SFR in Michigan. I am looking into some larger residential properties in the area. My question is: Is there a good rule of thumb you use when researching potential properties on how much net profit you will make per unit? I understand it could be different for each investor, but I am curious about what some other investors think. Thanks in advance.