Serious question: How do blind people know where to find the braille?

To be honest, it has me also. I mean some signs have typical placements or can be found fairly easily I'm sure but other times I really have to question their efficacy. I know when it comes to wheelchairs there are some setups that, while just barely ADA compliant, they are still pretty worthless or difficult for the wheelchair bound to use. It's maddening!