Virtually any investment real estate qualifies for a like-kind exchange. For example, improved real property may be exchanged for unimproved land and vice versa; an office building may be exchanged for a retail center; a farm or ranch may be exchanged for an apartment building. However, real property held for personal use, such as a second home, will not qualify. A principal residence will not qualify for an exchange; but, if used by the taxpayer as a principal residence for at least 2 of the 5 years preceding sale, such sales are not taxed except for gain in excess of $250,000 ($500,000 for joint returns).