They said that the drywall was saturated and crumbling in an 8x12 area, and the repair man said the leak has been going on for a while, possibly before they even moved in, but I didn't notice it when I bought it.

In secondary markets, our investors are picking up deals in their first couple of mailings, in the competitive markets a lot take 4+ mailings over a longer period of time because the markets are saturated with mailings and it takes a lot more sustainment for the letter to arrive at the right time for the seller to act.

Obviously, if such a thing existed the market would be over-saturated.

I think this market is saturated so I'm having a hard time finding anything worth while.

The space could get saturated quick by competition (big and small).

Unemployment, what is driving the employment in the area (big industry is key), what is the income to affordability ratio, how does the single family market look (strong, higher value SFR means more people have to rent), what are the current/future rent forecast in the area, what is the crime in the area, vacancy rate and the building industry/growth (saturation in your property class can be an issue). 

Sometimes we find a deal through a referral or MLS, but it's rare.Question to those who do similar or more volume: Realistically, how can we up our game beyond direct mail, which we've essentially saturated?

I have briefly looked at Memphis, I am mostly afraid about investor saturation in that market. 

Drywall sucks water so unless you have a moisture meter it can be hard or impossible to tell what is saturated. 

If it's saturated with open rental listings (4+ or more IMO),  you may have trouble getting what you want, especially if your house doesn't stand out from the pack finish-wise.