A well-known cat food company has changed its slogan to "Whiskas - Be Happy". But, before being outraged that the company is dumping "8 out of 10 cat prefer Whiskas", we should point out that that slogan actually disappeared two years ago.
Kit Kat dumped "Have a Break, Have a Kit Kat" for something more modern (which I cannot remember). And personally I cannot buy Starbursts anymore, because I refuse to call them anything other than Opal Fruits ("Made to make your mouth water") and nobody behind a shop counter now knows what I am asking for.
Some of the great commercial catchprases of recent years can be found at the Advertising Slogan Hall of Fame, but if you have a great adline, why change it? What are your favourite adlines that have bitten the dust? And have some of them only become well-remembered because they disappeared?