Do most towers worth visiting have audio guides or informational plaques?

Yes. Almost every major tower with tourist traffic offers audio guides, informational plaques, or both—like the Leaning Tower of Pisa, the Eiffel Tower, and the CN Tower. Geology gets less attention than history, but it’s usually covered if the tower’s structure or location is geologically interesting. For smaller towers, check their website; if they don’t mention them, read Wikipedia beforehand and look at the view. The audio tour is worth it if you’re into context; otherwise, the plaques will do.