"Personal residence" refers to the place where an individual lives and considers their home. It is a term used to distinguish one's primary living space from other types of buildings or properties one may own or occupy. Full definition
The allocation rules only apply to time periods prior to the conversion into a principal residence and not to time periods after the conversion out of personal residence use. (havenexchange.com)
One of the smartest financial decisions you can make when investing in rental properties is to actually buy the properties as personal residences. (greenresidential.com)
FYI: The capital gains exemption for personal residences has or soon will change. (biggerpockets.com)