daemon to auto-renenew Kerberos tickets?

hello,

let's say i run 'kinit --renewable' and get a ticket with a lifetime of 
10h which is renewable for 5d.  is there some kind of daemon i can run 
that automatically renew this ticket until the renewable period runs 
out, until i log out?

using MIT Kerberos for Windows, this happens automagically as long as 
i'm logged in, but i can't find any way to do this in FreeBSD.

i understand i could crontab 'kinit -R' or something like that, but i'm 
hoping for something that does this only for logged-in users, but also 
for all users who are logged-in.