A319 starts to go next year, 777 will fly for 30 years and a few jumbos will be here in 10 years time.

BA keep their aircraft quite a while but there are many airlines that keep them much longer. Being the sad act I am I was looking through the L/N for the A320 last night to see how many have been scrapped and Lufthansa are notable for having a lot of circa 1990 machines in service still.