Custom lists are limited to a total of 256 characters across all items in the list. This means that the number of characters in each list item affects how many items you can include in the list.
For example, if your list items were each 50 characters long you would only be able to have a maximum of 5 items. If your items were 10 characters long you could have 25.
You'll be happy to know, however, that you can bypass this limitation by placing your list items in cells on a worksheet. You can then use the Import option to specify the cells that contain the list items, allowing you to create a custom list that isn't constrained by the 256 character limit and is only limited by the size restrictions of an Excel workbook (over 1,000,000 rows).
You can see more about custom lists in the video lesson: Expert Skills Lesson 1-16 Sort a range or table by custom list.
For more about the size restrictions of the Excel workbook format, see the video tutorial: Essential Skills Lesson 1-5 Download the sample files and open or navigate a workbook.
I hope this is the answer that you were looking for, but please feel free to reply if you need any more help with this.
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