Your TRA Carpenter and Joiner skills assessment is valid for 3 years from the date the skills assessment is issued. This means you need to have received your Invitation to Apply for the Visa before the 3 years is up.
As part of the Carpenter and Joiner skills assessment you will receive an Australian Certificate III in Carpentry and Joinery. This is a qualification that will help when looking for work as a Carpenter and Joiner in Australia and has no expiry date.