Years of wear can cause a carpet to pucker and develop wrinkles. Cleaning is great in these cases, but the only way for your carpet to really look like new is by having it re-stretched and repaired.
Wrinkles in your carpet can be caused by any number of reasons, including heavy traffic, sliding heavy furniture without sliders, improper installation, water damage, over tucking and under stretching. It is important to have the wrinkles stretched out of your carpet because as the yarn bunches, it will gather more dirt. If left untreated for too long, the backings will separate, causing the carpet to unravel.