Where should I put an administration page that should only be used once?
I am creating a plugin that will index all used HTML tags in your posts, so you can cleanup posts if you change themes and want to replace old incorrect
<font> tags with headers or other semantic markup. When you install this plugin it should scan your old posts once to fill up the index (custom taxonomy). I don't want to do this on plugin installation because it might take a long time if you have many posts, and thus a separate page with an AJAX-approach to transform batches of posts might be better.
It's probably nitpicking, but should I put this extra page in the menu (under Tools?) and just leave it there, or should a use a trick to only display it when needed? Via a link in the plugin actions, or maybe a DB setting that you can use to hide the menu item? The plugin should remain installed (because it updates on post inserts and edits), and maybe sometimes you want a rescan (if you did a bulk change via the database).
As plugin users, does it bother you to have menu options that you almost never use?