Lipitor is a medication used to lower cholesterol levels in the body, which can lead to a decreased risk of heart disease and stroke [1]. However, the sources provided do not mention any information about how often Lipitor users should stretch.

Stretch marks, on the other hand, are a common concern for many people. They occur when the skin is stretched rapidly, causing small tears in the dermis layer of the skin [2]. While stretch marks can occur for various reasons, including pregnancy, weight gain, and puberty, there is no clear evidence to suggest that Lipitor use is a direct cause of stretch marks [2].

To treat stretch marks, there are several options available, including topical creams, laser therapy, and microdermabrasion [2]. However, the best way to prevent stretch marks is to maintain a healthy weight, stay hydrated, and avoid rapid weight gain or loss [2].

In conclusion, the sources provided do not offer any information about how often Lipitor users should stretch. While stretch marks can occur for various reasons, including weight gain, there is no clear evidence to suggest that Lipitor use is a direct cause of stretch marks. To prevent stretch marks, it is important to maintain a healthy weight and avoid rapid weight gain or loss.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.everydayhealth.com/skin-beauty/stretch-marks-why-they-happen-and-how-to-treat-them/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463373/