Advil is a brand name for ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, fever, and inflammation. According to the official Advil website [1], the recommended dosage for adults and children over 12 years of age is 1 or 2 tablets every 4 to 6 hours, not to exceed 6 tablets in 24 hours. However, the dosage may vary depending on the individual's condition and medical history, so it is important to consult a doctor or pharmacist before taking Advil or any other medication.

It is also important to note that ibuprofen should not be given to infants under 6 months of age without a doctor's recommendation [3]. For children between 6 months and 12 years of age, the dosage should be based on their weight and age, and should be given every 6 to 8 hours, not to exceed 4 doses in 24 hours [3].

It is not recommended to take Advil or any other NSAID for more than 10 days without consulting a doctor [2]. Prolonged use of NSAIDs can increase the risk of side effects such as stomach bleeding, kidney damage, and heart problems [2].

In summary, the recommended frequency of Advil intake for adults and children over 12 years of age is 1 or 2 tablets every 4 to 6 hours, not to exceed 6 tablets in 24 hours [1]. However, the dosage may vary depending on the individual's condition and medical history, so it is important to consult a doctor or pharmacist before taking Advil or any other medication. It is also important to follow the recommended dosage and not to take Advil for more than 10 days without consulting a doctor [2]. Finally, ibuprofen should not be given to infants under 6 months of age without a doctor's recommendation [3].

Sources:
[1] https://www.advil.com/faqs-en/advil-pain/
[2] https://www.healthychildren.org/English/safety-prevention/at-home/medication-safety/Pages/Ibuprofen-for-Fever-and-Pain.aspx
[3] https://www.drugpatentwatch.com/p/tradename/ADVIL