Mutable strings: That depends on the type of application you're doing. In my area, gamedev, it is better that everything is mutable by default and you optin for

Mutable strings: That depends on the type of application you're doing. In my area, gamedev, it is better that everything is mutable by default and you optin for immutable, since games normaly deal with structures the mutate every frame. In that scenario it is normal to have immutable things getting in your way more than the other way around.