For gallbladder polyps greater than 1 cm, cholecystectomy is generally recommended. For gallbladder polyps less than 1 cm, follow-up and management have been conflicting but recently attempts have been made to reach consensus/joint guidelines. Here is a sample algorithm published in 2017: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544788/figure/Fig1/
Polyps can develop in any organ. These days the current suggestion is if a polyp is present, no matter what the size of that polyp, that the gallbladder be removed.