As a rule of thumb, how much is reasonable to spend on home and personal security?

I am asking for an answer as a percentage of the asset value.
For example, the rule of thumb for a hunting rifle is the optics should cost between 50% and 100% of the value of the rifle. You put an expensive scope on an expensive rifle and an inexpensive one on cheap rifle.
Is there a similar rule for home security? If your home and property is worth say $1 million do you invest 1% of the value, $10,000, on a system? What if everything is worth 1/10 of that ?
How much of your time and money is spent on security, like locking doors, installing locks, and monitoring equipment? Are you checking cameras constantly?
We spend very little and don’t lock doors.
(Do you know where our front door key is hidden? We don’t know either.)
What about you?