FOH Online is has a story about the Cadac A-Type console in use for The Phantom of the Opera, which has been in constant use for over 18 years and has only required routine maintenance. It's a fascinating read, IMO.
http://www.fohonline.com/news/news.php?sCode=06022001.txt&st=0
http://www.fohonline.com/news/news.php?sCode=06022001.txt&st=0