Every house is different and prices fluctuate greatly depending on the style, type of construction, how many stories, age of the house, location, etc.

Inventory changes are fraught with wild fluctuations, see the Yoy % change graph.

Commercial real estate investors can share a lot about the challenges of collecting from churches - especially if income (collection plate) is fluctuating. 

As of now the markets are going up and providing good price appreciation which can give you net returns that are higher than looking for cash flow but the problem is that when you add time into the equation the markets tend to fluctuate and may even turn negative.

I did not become a short sale or REO agent, and my business continued to grow right through the fluctuations.

That’s where the cash flow comes into play, if this property was cash flowing $0 to some positive number a month the fluctuations in price would be easier to swallow as the investment would still be cost neutral or making money and it would be less painful to wait for the upswing in the market you would be looking for to sell and make your gains.Just my two cents

Expenses will fluctuate but if you ask for the last months utility bills you should be able to get a good idea of the predictable expenses like that.

Gold can have much larger price swings and doesn't have the potential of creating a passive income stream.Real estate values can fluctuate as we all have learned, but I believe if you looked at gold over a significant period of time you would see that it more volatile.

Appreciation => Speculation, variation, marketing fluctuations and uncontrollable.Cash Flow => dripping faucet, straight into your bank account, month in, month out.I bought in '97 a cash flow with a DSCR of 1.15 on a MFU 6-unit (squeaked in). 

I would consider that both markets are very cyclical and prices fluctuate a good deal depending on the phase of the market cycle we are in...