In common law systems like America yes precedent is extremely important. Generally courts must defer to precedent But sometimes long established precedent is w

In common law systems like America yes precedent is extremely important. Generally courts must defer to precedent But sometimes long established precedent is wrong and must be overruled. https://en.m.wikipedia.org/wiki/Brown_v._Board_of_Education https://en.m.wikipedia.org/wiki/Brown_v._Board_of_Education An example where the Supreme Court famously said a then 58 year old precedent was wrong