It’s always struck me as kind of weird that a 10-foot pole was something you bought at a store. What kind of store sold it? A carpetry supplies store? An adventurer store, sold specifically for the purpose of tapping suspicious flagstones in ruins? Speaking of flagstones, could the 10′ pole possibly have been sold as a flagstaff?The pricing of the 10′ pole has led to much mirth. The 10′ pole, unbelievably, made it as far as edition 3.5, where it sold for 2 silver pieces. A 10′ ladder sold for 5 copper pieces. The joke was always that for the price of a 10′ pole, you could buy 4 10′ ladders, remove the rungs, and end up with 2 10′ poles, which you could sell for a profit. Classic D&D economics.
The 10′ pole is also a classic disappears-while-not-in-use item, like a wizard’s familiar. My mind’s eye picture of a 10′ pole is of a guy probing the floor with a stick that is clearly 5 or 6 feet long. 10 feet is about twice as tall as a person! Someone carrying one around would really have to have it in one of their hands, meaning they couldn’t have a shield or torch in their offhand. How else would you carry it? Strap it to your back? Horizontally? You’d have to turn sideways to go through doors. Vertically? You’d have to duck or bow. It would totally prevent you from crawling through any network of twisty little tunnels, all alike.