In a system at $WORK I recently optimized a structure from String to Box<str> (similar optimization to remove the 8 byte capacity field) and saved ~16Gb of memo

In a system at $WORK I recently optimized a structure from String to Box<str> (similar optimization to remove the 8 byte capacity field) and saved ~16Gb of memory. Granted, the program uses 100-200Gb of RAM at peak, but it still was a nice win for basically no work. It's also a semantic win, since it encodes "this string can't be mutated" into the type.