In Cincinnati, it is common on older 4 families for LL to pay gas, and that can be a very expensive bill. 

It seems common sense that investors wouldn’t want to buy properties in a dangerous neighborhood, etc.

@Ramon Flores I've seen agents work together if they are under the same brokerage, but it's not all that common.

Is this a strategy that is commonly used or is the real estate commission worth the saved time/effort?

I think that’s very common and is a great goal for a lot of newer investors.$200/month can be the start of something much bigger.

There's also common variations in the spelling of the last name.   

I'm encouraging seller-financed noteholders to consider small partials as a way to raise cash. 12 - 24 months on 60+ outstanding payments will result in a minimal discount because, in the most common partial scenario, the buyer is buying near term payments and taking less equity risk.

I would rather have at least one bathroom open up to a common area for access to everyone. 

If she doesn't act on the advice and continues to see this person (which is common), I don't want to have to inconvenience my other tenants by changing the locks again.

Common sense!