There are neighborhoods where it is impossible to park a bike for more than fifteen minutes or so. When I go to such neighborhoods I take a twenty year old bike that has faded and scratched paint. Looks horrible, and rides great.

I've replaced the quick releases with bolt-on skewers on the wheels and seat, and use massive u-locks to secure both the rear wheel and the front wheel to steel posts that are set in concrete.

When possible, I lock next to a new Cannondale that has only a cable lock. Crooks have good taste and they are lazy. They will steal the new Cannondale.