Medium-term goals are set to be achieved somewhere between a person's short-term goals and his long-term goals. Since long-term goals can take a long time to achieve, medium-term goals help a person stay motivated while he is taking the day-to-day short-term steps necessary for steady progress towards long-term goals.
SparkPeople notes that after a while, the daily tasks associated with achieving long-term goals might begin to seem boring. Also, there may be many steps involved in reaching the end goal and focusing on so many different steps can be overwhelming. This is where medium-term goals come in. They act as milestones that can be celebrated along the way to the end goal, and they serve to keep a person motivated and excited about the journey toward the long-term destination.
ZenHabits.net advises people to focus on just one goal at a time. The website recommends starting with setting a big-picture life goal and then deciding on a related goal that can be achieved within a year. Once a one-year goal has been chosen, a person should create just one medium-term goal that can be accomplished in three to six months. Next come the short-term goals, which should consists of tasks that can be done in one to two weeks.