Right now I'm just typing in "rent house in (zip code)" which gives me a general idea, but there aren't usually a lot of properties that also have the same amount of beds/baths, square footage, etc.Is there a better way to estimate rental income?

Not only that, but it has a feature called a Fixed Asset Items List which you can CUSTOMIZE to tell you anything you want to know about this property.You can design it to give you the Land Description, the year it was built, Square Feet. 

Just like your plumber, call him while you have a drip, not after you have two feet of water in your basement.

If basement not only can the carpet get thrashed but the subfloor and first 4 feet of the drywall with animals.

They know approximately what it would cost to replace copper per square foot in an area.

Bird-dogging is a great way to get your feet wet.

Many cities will limit the square footage of the ADU, some will require stick built, some even allow mobiles.

Thus they back off and the price drops till it gets its feet back under it again.  

Now I could raise rent to $800 or possibly $850 per month as it is a 4 bedroom, 2 bath house of 2,000 sq feet with a garage. 

Room occupancy goes by ages and gender, a square footage minimum for each occupant of a bedroom, if it's big enough, you could have 3 brothers or sisters at certain ages.