it depends on where are you going, i know for sure that Europe accepts 3-months validation passports hmm i even went with my RTD to Germany and no one told me that you aren't allowed to get in and the RTD was only 2 months away of the expiration date!!! countries do that 6 or 3 months validation rule so that if you lose your passport or RTD you don't overstay there as the embassy of your country or where you permanently live take 1-2 months to process you travel permission to let you board on the flight back to where you Came from.
again, most of the world countries requires you to have 6 months only Europe requires you to have 3 months and sometimes they don't even care about that but don't Risk it anyway and call the embassy of where you are heading to and ask them just to be 100% sure about it.