User stories or other items that are likely to be more distant than a few iterations can be left as epics or themes. These items can be estimated in units beyond the 1 to 8 range I recommend. To accommodate estimating these larger items I add 13, 20, 40, and 100 to my preferred sequence of 1, 2, 3, 5, and 8.
Estimating Epics and Themes in the Product Backlog...cut down on unnecessary user story creation and estimation.
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