Can I ask why the renewing bother you ?
The fact of a renewal doesn't worry me, it's that every time it does renew, the connection is lost as the client reconnects. This is a problem for one PC that is always on and is hooked into weather reporting equipment and onto the Internet, so ideally needs to be up 24x7x365 (an impossible dream, I know). The fix is to use an assigned IP address, rather than DHCP (even if the same address always get re-assigned) and that will be the way to fix that one device.
But we also have several laptops that I use the Cisco VPN client on and they may be online for ages (certainly a full working day and often well into the evening) and as I am running SSH protocols to command line sessions on large Unix servers - think Sun Microsystems gear, typically with 32xCPU and 256Gb RAM - for system admin tasks...
I cannot use those devices over my wireless link with confidence if the session 'dies' due to a 'pointless' lease renewal.
Can't use static IP assignments on these devices as they also 'roam' to other wireless locations, so would need to go from DHCP and back to static all the time... a real pain!!!
Don't try "0" it's not "never expire" 
Ha! Thanks for the tip.
Anyway, that's
why I asked.... I really would like to set the the DHCP lease time to the upper limit, to reduce my "problem".
