Thanks guys.
Ive got 4 rods and 2 licences myself and theres no restrictions on the waters I currently fish.
I've never had 2 runs at the same time and whilst it could happen I recon the chances of 2 or more similtaneously would be slim.
I wasnt sure if fishing 3 rods was something to do with covering the water without putting too much pressure on, but as you say its more often down to the water restrictions which I hadnt considerd.
Makes it prity pricey to fish one extra rod then on some waters!