Every two weeks i get this:

$ xterm &
Xlib: connection to ":0.0" refused by server
Xlib: Maximum number of clients reached
xterm Xt error: Can't open display: :0.0

and it looks that something eats up the possible number of Clients:

$ xlsclients |wc -l
56

when i restart X i can open about 100 xterms until i reach the error message.

ideas?