Often logging backends have a sampling rate to take care of this for you. As it is almost certainly better to setup a buffer in your logging layer and deal with this there, than to try and do this everywhere in your code.
This feels like one of those "not obvious until you've seen it in production" requirements: any production-ready logging framework should have a mechanism to delay parameter evaluation until after the threshold/destination checks are performed. Most languages have some version of deferred execution (lazy evaluation, thunks, etc.)
