Ask HN: What do you use as a home surveillance system?

Personally, I live with just my wife and we have a WiFi single camera that watches the inside of our part of the duplex. It covers all the entrances and has a great view of everyone who comes and goes, and since we're the only one with access to it it's great to keep an eye on things when we're away.

I have backup footage stored on a NAS in a locked room, but lately, I've been feeling slightly more paranoid and have been wondering whether I need more cameras and probably an off-site backup.

I suppose the paranoia that makes me good at engineering infrastructure is edging at me to upgrade my tiny WiFi camera + NAS setup into something more robust like encrypted periodic updates to S3 that are purged every 90 days, with an NVM that stores only clips of movements from Power-over-Ethernet cameras that monitor the multiple architectural weak points of my house.

I also live in a developing country, and while it's fairly safe, it's not that safe.. I want to be able to elevate monitoring levels to red when I leave and be sent a picture of (hopefully not) a mouse running around. Or set monitoring levels to yellow when I go to sleep and be alerted to someone accidentally trying to enter my house thinking it's theirs.

Do you have an over-engineered home surveillance system? What did you use?