Well, I don't. I don't like the paint and I am no good at sticking the foil. I do however use shielded cable in my builds and I have yet to figure out why more folks do not do this. Sure it is not all over the pick up route, but those things are there to pick up noise, so I let them. As long as I am not making an antenna with the wiring then I don't bother.
Now, active electronics and active preamps are a different story. They should have the box shielded, like a stomp boxes shell is. A lot of components in there pick up noise really easily.
If anyone is wondering where to get shielded wire,
Hoffman Amps has it for 32 cents a foot. Buy extra, make decorations, build a tube amp... It is really easy to use, works well. My 2 cents.
Patrick