Changing plugs on a car - will it improve anything??

The plugs in my Renault Scenic have done 11,000 miles; I will be replacing them as soon as I can, as it seems to be running a little lumpy.

Check what the change interval is first, some cars running Iridium plugs have a service interval of 50,000 miles or more.

The plugs are about a tenner each, so you don't wanna change those after only 11,000.

I was told by an AA mechanic that plugs eventually break down & allow too much current to pass. This leads to the failure of the ignition coil pack.