Enter the interval, or the number of years between each repeat. An interval of 1 (the default) means "every year". An interval of 3 means "every three years". For example, if you've entered a Start Year of 2030 and an Interval of 2, the amount shown in your plan will occur in 2030, 2032, 2034, and so forth. Click "Preview" to see how your entries will look.