Creatine is a somewhat rare supplement in that there is plenty of evidence that backs its use. It improves strength, enhances recovery, and increases muscle mass. It does not however, work on every activity. The evidence on creatine use to improve aerobic activity, high intensity exercise, sprints, and decrease body fat is at best, mixed.
Cycling creatine on and off is unnecessary. There is no good research indicating that long term creatine use has any negative effects. The ISSN’s stance states that use of up to 30 grams per day for periods as long as 5 years is safe. Most research indicates as little as 3-5 grams per day is enough to see benefits.