I almost made this mistake. I planned to return to the Hong Kong Museum of Art gift shop to purchase a book I'd seen there on Sunday. I consulted my guidebook and found that the museum was closed on Mondays, so I made plans to stop by later in the week. Luckily, Mez pointed out that the hours had changed since the guidebook's printing and that the museum was closed on Thursday, not Monday. This saved me a potentially disappointing trip.
Maps are everywhere.
We picked up a map and some brochures in the airport, then received another map from our hotel when we headed out the next morning. Later, we purchased a small, laminated map that we knew would withstand being folded, unfolded, and stuffed into a bag or pocket several times a day.