Depending on the topic at hand, researchers generally set aside an hour and a half for focus groups.  Some may be as quick as one hour while others may run as long as two.  Participants will be notified prior as to how long the focus group is intended to last and researchers will do their best not to go over this time frame.

Sometimes it is hard to say exactly how long the group will last and the client or researchers will give the maximum time of two hours.  The group may not run this long, this is just in anticipation that it could last this long and they want participants to plan accordingly.  Also depending on how in depth the conversation, if participants agree to stay, the group may extend further than the allotted time.  It all depends on the topic being discussed and if the researcher would like to try and gather more information.

Of course, if you are working with children, the younger the children, the shorter the group should be.  Younger children have shorter attention spans and will begin to lose focus and interest in the topic rather quickly. Older children may have slightly longer attention spans and may be able to withstand a longer discussion.