"I believe that the analyst community, as hard as it is trying to understand cap ex in the apartment business, hasn't gotten it yet," Sweet says. "They really don't understand the cost of running an apartment community the way they need to be making some the distinctions they're going to make."

Rules of thumb on how much capital expenses should run range from $200 to $350 per unit, Sweet claims, across various markets and product classes. "That number has a chance of being an OK number on brand new units that have just been built by someone else or bought," Sweet says. "In the early years of an apartment community, there aren't as nearly as many items of capital expenditures needed."

About seven years down the line, Sweet suggests, items such as carpeting and appliances need replacing.

"Many of the analysts don't have the time to dig down into a company's particular structure, the age of their assets, where they're located…so they've kind of standardized where they think the cap ex number should be," Sweet says. "That number is anywhere is anywhere from $400 to $600 per unit and is applied almost indiscriminately among the various apartment companies they follow."

Sweet says AMLI's 10-year history indicates capital expenditures range up to $325 per unit across its 30,000-unit portfolio across eight markets.