When to use ik n when to use fk ?

One of the most commonly asked question is is ik better or fk.And the ans is both :). It depends from situation to situation. Most people like to use fk in walk cycles and actions the reasone for it that fk gives us an automatic arc and saves us time and give more realism but if the scene includes character to put his hand or pick an object its best to use ik though you have to add more keys to make it move in arc's but it will still save you time bcoz in fk you got to keep giving keys manually where the object is moving and trust me you will go crazy in order to make it look smooth couz there will be so many keys and graph to clean so in those cases it will be better to use ik.