How do you smoothly take one off, and put on the other?
I have two glasses that I like a lot, so getting another pair with transition lens is not an option.
You can actually buy a pair of sunglasses that come with a coating that changes the lense from indoor to outdoor automatically.
However, if you already have a pair it does not have any effect to change the glasses while still indoors and walk outside with the sunglasses on. It will not harm your eyes