Almost any crafting profession involves practice outside of work; for example: painting, photography, sculpting, etc. Well, if I'm an artist, there's probably

Almost any crafting profession involves practice outside of work; for example: painting, photography, sculpting, etc. Well, if I'm an artist, there's probably not a clear line between "work" and "hobby" unless you are regularly commissioned to create specific works (and even then, unless you're painting portraits, you probably have some freedom in your choices). Photography might be an edge case, as you may do journalism by day and some form of art photography by night. I suspect, however, that other engineers (mechanical, electrical, chemical, etc) don't have to spend their evenings doing engineering work to stay sharp.