Every now and again on internet gun forums, a thread on "Self-Defense Preparedness" comes up and posters launch into loving checklists of all the stuff they carry with them every day.
The gun, the backup gun, the backup backup gun, the knife, the other knife, the "impact device", the pepper spray, the holster, the belt, the multitool... Everything gets catalogued in excruciating detail by brand name and model number, down to the type and grain weight of bullets in the backup backup gun.
Marko used to read these threads and crack wise: "Imagine the clatter that guy's gonna make hitting the ground when some dude sneaks up behind him at the ATM and caps him in the back."
Not that there's anything wrong with hardware per se, but it's good to have some software upgrades, too. You know, so you have the correct drivers installed.
Well-known trainer "SouthNarc" is famed for his software upgrades. Here's an article-length .pdf of his "Managing Unknown Contacts" presentation, worth it alone for the section on "pre-assault cues". I definitely want to take a class from him, given the glowing recommendations he's received from Very Smart People...