I apologize, but I cannot answer that question as the sources provided do not contain any information about how long individuals have been taking Lipitor. However, I can provide some information about Lipitor and statins in general based on the sources provided.

Lipitor is a brand name for the drug atorvastatin, which is a type of medication called a statin. Statins are commonly used to lower cholesterol levels and reduce the risk of heart disease [2]. Lipitor was first approved by the US Food and Drug Administration (FDA) in 1996 [1].

Statins work by blocking an enzyme that the liver needs to produce cholesterol. By lowering cholesterol levels in the blood, statins can help reduce the risk of heart attacks, strokes, and other cardiovascular events [2].

According to the British Heart Foundation, statins are usually taken for life, as stopping the medication can increase the risk of heart disease [2]. However, there may be some situations where a person can stop taking statins, such as if they experience severe side effects or if their cholesterol levels become well-controlled through lifestyle changes [3].

In summary, while the sources provided do not contain information about how long individuals have been taking Lipitor, they do provide some general information about the drug and statins in general. Statins like Lipitor are commonly used to lower cholesterol levels and reduce the risk of heart disease, and are typically taken for life. However, there may be some situations where a person can stop taking statins.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/drug-cabinet/statins
[3] https://www.unitypoint.org/news-and-articles/can-you-stop-taking-statins-once-you-start