Keep It. Gallbladder polyps typically do not cause a problem. Unless you are having pain in the right upper abdomen or the polyps grow larger as measured on 1 year followup ultrasound, you should be able to keep your gallbladder.
One centimeter. Gallbladder polyps of less than a centimeter in size have a low risk of harboring malignancy, but the risk begins to increase with polyps larger than that. Given the low risk of gallbladder removal and the poor prognosis of gallbladder cancer beyond the very earliest stages, in my practice i recommend removal of the gallbladder for polyps > 1 cm, and periodic ultrasounds for smaller polyps.