Is this
one workbook going to be used by only one user. After making choices, some sheets will never be seen again.

or

one workbook is used by several users. Each user makes their choices and the wb detects which user opens the wookbook, showing them the applicable sheets.

If case one, why not delete the unneeded sheets (on initial questioning) rather than hiding them. Then the Open event can show all the sheets, included any added ones.

If case two, make a list for each user of the needed sheets. Any sheet a user adds during their session should be added to their list.