I picture a scummy half way house but I'd like to think there are good operators out there.

Then 10 years into it, my cash flow was up to $30K/year, including covering several thousand a year in small nuisance repairs.

It's all a game of creating barriers of exposure to your other assets and if you have a big enough accident at your property, insurance will not cover it most likely. 

Plus, you'll want to create an upfront operating account of 1% to 5% of the purchase price to cover unexpected expenses before you've accumulated enough money for the $250 to $300 savings.For SFRs or smaller multifamily, as you said, it depends.

@Gab Loo @Hannah Peerbolt wrote a good blog that covers a lot about what to look for in your property manager.

My goal is to do a full 20, get out at 42 years old, and be done working with enough money to cover expenses + have ~$10K/month excess.

This is where I live - my 3 apartments cover my mortgage and I am in essence living here “for free.”

@Josue Velney That doesnt sound unreasonable at all . 10% gets you on the schedule , covers the paperwork time and phone call time to get the job up and going .  

@Sam Shueh the CapEx covers those items you mentioned, its pretty much any of the big ticket items that don't go out too often (hopefully).

If I can figure out how to add a picture from my phone I will, or I'll definitely add tomorrow.