Extension strategies aim to prolong the maturity stage and not let sales decline. Making modifications to the 4P's will help to do this.
Some ideas include:
Modifying the product and adding new features
Promoting the product
Developing complementary products such as shower gel for a luxury frangrance range
Finding new uses for the product
Attempting to encourage uses - for example Special K cereal bars
This graph looks familiar:
What extension strategies have Apple used?
How many of THESE Sony products have you used? Do you think Sony is as succesful as Apple in re-inventing itself?
Ultimately if a business does not extend its product life cycle and re-invent itself, it risks ending up like Polaroid who went bankrupt.
Source: Tutor2U and the graph was scanned from iCreate magazine - issue 99 The article also includes an interesting piece on why the ipod was so successful and discusses the contribution of advertising and design.