how old is old - indexed content

[chillfire]

I have a few sites that I look after that getting on a bit now, with some content that has been static for over 2 yrs, google still seems to be spidering these pages and they are still ranking fairly well, but does anyone know if there is a 'die' date for content that has not been updated?

I mean will it just one day disappear from the index?

cheers,
craig

[P.O.S.]

Well for me as long as it's ranking very well for my targeted keywords then there's no need to change the content, maybe just a few additions to it. But if it's not ranking well, I do change the content, a little experiment on this and that there's really no formula for the perfect content, it's like a trial-and-error thing what's more important is the quality of the content.