The short answer almost every guide gives — "buy a disc lock" — is correct, and it is also where most guides stop. A disc lock earns its reputation because its shackle is buried inside the lock body, leaving bolt cutters almost nothing to bite (Extra Space Storage). What the advice rarely tells you is how to judge one disc lock against another, which security claims are verifiable, and which part of your door is the real weak point. I design lock bodies for a living, so this