The date of death for most of them can be found in Foxe's Book of Martyrs.
It can reasonably be assumed that the Discipes were at least 20 years old at the start of Jesus' ministry in 27A.D For the sake of argument, I will assume they were all born by 10A.D., and all ages at death are a minimum.
St. Matthew was murdered on the streets of Nabdah, Egypt in 60A.D.
That would make him at least 50 years old when he died.
The earliest copy of the book of Matthew, recovered in an archgeological dig, is known as the Mitchell text and was dated to 54A.D.
The last known record of St. Mark being alive is found in Colossians 4:10.
Colossians was written by St. Paul around 61A.D. Therefore St. Mark lived to be at least 50. The book of Mark is believed to have been written betwee 50-67A.D., but probably the former.
The best avaiable information on St. Luke is that he was hanged in Achaia, Greece around 71-73A.D. He was 84. The book of Luke was written around 62A.D.
St. John wrote the book of Revelation in 90A.D. His age of death is unknown, as he was in exile on the island of Patmos after the Romans failed to kill him by boiling him in oil. He was at least 90 when he died.
James (Jesus' brother) was stoned in 63A.D. The death blow came from a club that smashed his head. He was 94. The book of James was written between 44-49A.D.
St. Jude was crucified in Edessa, Greece in 72A.D. He would have been at least 60. The book of Jude was written in 50A.D.
I hope this clears up how they had long lives for their time and how they had time to write the scriptres attributed to them within their lifetime.
For further reference:
http://www.scionofzion.com/foxe1.htm
27 Apr 2005, 9:40 pm
