I go down a hallway facing forward.Because what happens is I go down the hallway facing the wall (not really paying attention to what's in front of me), then back around the same hallway, this time facing the other wall, on the off chance there might be one of those wall buttons I missed.
I usually see the buttons as I pass them.
I will scour the walls if I reach an obvious dead end that had little in it, or if there is a locked door.
Otherwise, the button isn't THAT important, and only has something optional behind it.
For those, maybe I'll eventually go back, or play the game again looking for secrets.
Like the Lurker Boots. I didn't get those until I walked back from floor 7. No big deal.