People pay for insurance every month without complaint — car insurance, home insurance, health insurance — accepting the cost as the price of protection against something that might never even happen. Almost nobody thinks about legal knowledge the same way, even though it protects against situations that are far more likely to actually occur.
Knowing your rights during a traffic stop, knowing what a debt collector can and can't legally do, knowing that a foreclosure or eviction has real required steps before it can happen, knowing a deposit dispute has an actual process — none of that costs a monthly premium. It costs the time it takes to actually learn it, once, and then it sits there protecting you for the rest of your life, the same way insurance does, without ever needing a renewal payment.
The difference between insurance and legal knowledge is that insurance pays out after something bad happens. Legal knowledge often prevents the bad outcome from happening at all, or shrinks it significantly, by changing how you respond in the moment instead of just cushioning the aftermath.
Most people will never total their car or have their house burn down, and they still pay for that insurance anyway, because the cost of being wrong is too high not to. The odds of eventually facing some kind of legal situation — a dispute, a debt, a landlord, a contract gone wrong — are considerably higher than either of those, and the insurance for it is free.