That's one thing I've noticed with my C++ code lately is that I'm writing const absolutely everywhere. Having mutability where you need it is awesome but it is interesting to see languages like Rust where immutability is the default.
I've found using const a lot also goes hand-in-hand with raii. If a member of a class is const it must be initialized in the constructor, and it just seems to make me code a bit more "hygienically".