Since you are in California, the odds of it not being allowed are much higher (nanny state).

Cameras, fences, security lights, better locks on the main door, etc?

I also suggest installing cameras in common areas for security.

From time-stamped cheap camera photos to ALL CAPS TWO-SENTANCE DESCRIPTIONS, make sure to reference the agent's prior listings before deciding which one to use.

They do security cameras and intercoms.

I have a Vivint system in my house and the sun will sometimes set off the cameras.

I know some landlords even stay connect to the alarm on their units with an app just to monitor things but don’t include cameras (though that’s an option).With tenants moving out and that you buy the system you’ll be able to transfer the system to new tenants without a hassle.Installation and set is cake and very manageable without having to drill holes in walls or doors.

We've used Vivint Smart Homes in some of our rentals and a combination of Ring cameras, coded door locks, and  Google Nest in other rentals.

Eufy also has smart locks, various cameras of every kind imaginable, and a home security system feature also.

I have a decent scanner app (uses camera to snap pic of docs) and it's awesome for bank papers, contracts, etc.