The problem we see in the sale of an income producing property is that, unless you re-invest the gain you've earned, you'll pay back the depreciation you've written off on top of capital gains. . Many of us who own small rental units, can sell a few of the older types that require a lot of time and upkeep, avoid the tax gain upon the sale, and purchase a newer unit or multi-family building where higher rents and lower maintenance are appealing. Perhaps you own a business you operate out of your home, and write off expenses with it. If you upgrade your location and facility, you may be able to save a portion of the gain off this sale proportionate to the amount of value your business added to the value of sale. Farms most often fall into this category.
Vacant land is also eligible.
Say you sell some land and buy some duplexes or an apartment building. One of my favorite transactions is where you might sell a single or two-family rental, and roll the gain into a condo in a fun location, that is rented out as part of a resort and handled by a manager for you throughout the year. Please keep in mind that this information is not intended to be legal advise, or that of an accountant. I do offer it as a guideline in assisting you with the real estate transactions that accompany the expertise of these professionals. There are additional guidelines that may affect your particular situation.