The Chicago Association of Realtors'® specifically state "When you become a Dual Agent, you owe equal fiduciary duties at that point to both parties in the transaction, and you lose the ability to negotiate for, strategize and advise either one."

Bad contractors are one of the main reasons why first time investors never do a second deal.

One of the first deals I had (multi in an up and coming area) my buyer was paying cash and the deal was solid.  

Did anyone in one of the accounts die?

You and Him are filing one joint tax return. 

Quote from @Tove Fox: I live in California and am interested in purchasing my first investment property in an A or B neighborhood in one of the above states, ideally under $300k.

As our team has grown, it's become easier to cover responsibilities if someone quits, goes on vacation, or if we terminate employment, compared to when we had one or two homes. 

Here is one piece of advice When looking at areas to invest in check out this website https://www.areavibes.com/ its pretty cool it gives you a total livability score and rating for that areaBest of luck!

My goal is to buy one rental per year with price between 150k-250k for the next ten years (if i get to keep my job). 

Quote from @Robert Zajac: 15% markup on maintenance is one of the highest I've heard of.