I have to say that after all the talk of disconnections and time outs I have had mine up for days.
I had decided to leave the router/modem on full time even though it is not used in the daytime and it has been excellent - Thank you Plus.net.
OK, so i'm on Premier and have a static IP but leaving the router on has been great.
I also can't emphasise enough the benifit of upgrading firmware, I have updated 3 routers over the last few days and can't believe the extra functions that have been added! - it seems much more stable too (all Linksys)