The exclusion for gain on the principal residence, which has been $250,000 ($500,000 on a joint return) since May 6, 1997, has been available for individual taxpayers as to “the taxpayer's principal residence….” The 1997 amendment eliminated the age requirement (which had been age 55) and the limitation to a one-time exclusion.
"Who Can Claim Exclusion On Principle Residence?,"
Agricultural Law Digest: Vol. 10
, Article 1.
Available at: http://lib.dr.iastate.edu/aglawdigest/vol10/iss7/1