Life always changes. Even if your dog is comfortable in all the places that are part of your daily routine now, you cannot be sure that routine won’t change at some point during your dog’s lifetime. It’s good to work with your dog on comfort in new situations.
Of course, the appropriate level at which to work on this depends on your dog. For more nervous dogs, taking a different walking route may be as much or more than your dog can handle. Confident dogs can handle a more challenging environment, but it still needs to be set to their level. I don’t recommend starting even confident dogs with a new environment that will require them to stay for a long time. Look for something that allows a quick exit.
In the DC-area, we have a number of dog-friendly bars and breweries, which can be a good place for this. Make sure you pick a time that the location is not likely to be too busy. Once there, you can work on whatever activity is appropriate for your dog, whether that is polite greeting, sit, or relaxed down. Remember to be respectful of other customers and your dog’s tolerance. Leave while things are still going well, rather than pushing past that limit. If things start to go poorly, leave sooner and choose a less challenging environment for your next adventure.