how long does a free site stay listed

[Linkster]

I am one in the camp of pretty much keeping everyones sites listed - however - with the number of sites that I started with (over 2000) that I stole from other LLs and wrote my own descriptions for - those are starting to go away, as well as of course the redirecting and 404s,etc type sites that we find every day.
Another criteria I use is since we hand check all links on a regular basis, and constantly find sites that have pulled recips or changed their code to screw surfers - and our reaction is to pull all sites submitted by that submitter - we can usually stay within the traffic numbers we want to send and the number of sites that are still a benefit to the surfers to promote bookmarking and more friendly sales for the submitters.