Tonsils should come out if they give you trouble

What actually happened

The scale of the old practice is hard to overstate. Tonsillectomy was among the most common operations performed on children in the mid-twentieth century, with well over a million a year in the United States, frequently done for vague indications. Jack Paradise's trials at Pittsburgh, beginning in the 1980s, found the benefit for moderately affected children was small and short-lived: the surgery reduced throat infections modestly for a year or two, against real surgical risk including hemorrhage, and children in the watch-and-wait arms improved anyway because recurrent tonsillitis tends to resolve with age.

The American Academy of Otolaryngology's 2011 guideline, updated in 2019, encoded the numeric thresholds and pushed watchful waiting as the default. The indications also shifted: the leading reason for tonsillectomy today is obstructive sleep-disordered breathing, not infection, and for that it works well.

A 2018 cohort study in JAMA Otolaryngology, following nearly 1.2 million Danish children, found removal in childhood was associated with increased long-term risk of respiratory and infectious disease, consistent with tonsils being functioning immune tissue rather than spare parts. So the operation is still valuable for the right patient, and far less common for everyone else.