Obligatory Zombie Post Emoji ===>

I felt some responsibility to update what I had posted way back when in case any one was looking through the annals of gun lore looking for information on the topic.
We are on our third iteration of home security.
2014: ZModo - $20 Proprietary Wifi System with one camera
2017: Amcrest & Blue Iris - $300 Wifi System with 4 cameras that we built up over time
2021: ReoLink - $2000 POE 8 Cam 16 Channel NVR
I will say that by far the Reolink system is by far the best system we have had with very comprehensive coverage. Knowing what I know now and having lived through the iterations of security I'd never go backwards unless I absolutely had to. But if $20 is all you got and you have t start at ZModo like I did then you are better off already
Things I have learned since installing the new system are that you want an NVR (all digital) rather than a DVR (old analog tech). NVRs are a full digital system. From the camera to the recorder. DVR's use an analog signal then records it digitally. Going with an NVR lets you get much higher resolution and is smaller on disk usage because it comes compressed from the camera.
When looking at your NVR, you usually want double the number of channels you intend to use. I have 16 channels but use 8 of them for 8 cameras. The reason is that the CPU inside the NVR is sized to the system with the understanding that if it has X cameras, usually only 50% will ever be activated and recording at one time. If you use an 8 channel system to record 8 cameras, you are really only getting an NVR that can accommodate 4 cameras at a time. It may be able to record 8 cameras at once but a lot of the systems (especially off the shelf system in a box) will struggle to do so. Sizing this way allows me to stream and record video from all 8 cameras at one time without taxing the system. This allows me to maintain functionality on windy days when the bushes and trees set off the system. It also allows me to pre-record 1 minute ahead of any time it records a motion event. So it is recording all cameras all of the time, but only saves the part one minute before the motion event. Nice way of preserving your disk space and having less to sort through.
Also - I was very confident in my wifi systems until one day I looked and there was a guy in my backyard doing some landscaping work (and we didn't hire a landscaper?!?) but how he got in the yard and past my locked gates was a mystery because there was no evidence on the camera. Wifi Cams were constantly dropping wifi signal and then reacquiring to the point that I'd bet they were off line for at least 30% of the time. The new system is POE - Power over Ethernet which means they are online 100% of the time. It also solves the janky problem of getting power to your cameras. Usually places that make a good vantage point are no where near where you want a camera mounted so you end up trying to hide extension cables and the like.
I wanted to get high resolution cameras and I can tell you these absolutely are. It's 8 megapixels of resolution. I wanted to be able to capture good solid facial features so that if you hand it over to the police, they can run facial recognition on it. I understand there exists, but I haven't gone looking for it yet, a service that can access your camera footage through the internet if you hook it up that will back feed you facial recognition data on who has entered your property. It's like caller ID for your door bell. Not just a visual on them but it actually gets you a name. CREEPY! Either way I wanted to have the ability to turn a face over to the police. I'm finding out that most perps now wear hoodies or caps and keep their head down so they can't be recognized by facial recognition. Covid masks don't help that either. To the point that if I had someone dressed like the stereotypical thief but on my lot with posture erect and face up they would be less suspicious than a slouchy girl-scout with her head down trying to sell cookies. Body language tells a lot here.
I had an Amazon driver drop off a package so just for grins I went back and froze the image to see how detailed the picture was. It got down to the small mole on his cheek and I could see the beginning of a tattoo poking above his collar. Detail is AMAZING.
Motion is one area I was not as astute on and maybe compromised where I shouldn't. I picked a system that records at 20 frames per second. The resolution is so good, I can snag plate numbers from the car across the street in bright day light. But if the car is driving, even slowly, I can't snag plates or details. Some vehicles with very distinct features (like a jeep) are discernible, but most of the sedans like a Corolla or Accord or anything made by Kia all look too similar to be identified. Occasionally the cams catch something like a unique tail light pattern that can be a clue but not a solid ID.
If I had it to do over, I would have gotten a system that had 30 frames per second or faster.
Cost.
The first system cost $20 per camera.
The second system cost about $75 per camera
My third system ended up running about $250ish per camera.
Here's how that breaks down
I got this system on sale for about $799 ==>
https://www.amazon.com/Security-Camera-System-16-Channel-Surveillance-Recording-RLK16-800B8/dp/B082KGF6FX/I got this battery back up for $200ish so the cameras will run for about a day if the power gets cut ==>
https://www.amazon.com/Tripp-Lite-Battery-Protection-OMNI1500LCDT/dp/B00AX9Z7R4/I paid these guys about $1000 to run the Cat-5 cables in the attic ==>
https://proskillservices.com/If you can run your own cables, you can save that 1k expense. In my case, I was recovering from Valley Fever and didn't want to do attic work - also I was recovering from being fat and didn't fit a lot of places that I needed a camera so hiring out the cable run meant the difference between getting the full value of the system or neutering it from the start with bad camera placement. Your circumstances will almost certainly vary.
I will admit that Blue Iris is a very slick set up and I do miss some of the features (would be nice if they made an NVR system) that I was getting with it on the Wifi cams but t ran my CPU 24/7. There's no way my computer would have handled more than 4 cameras so it would have meant upgrading to a new high performance and dedicated PC to run a bigger system. The Reolink User Interface is pretty basic but it gets the job done and with a much shallower learning curve than Blue Iris did.
HikVision is the leader in cameras and quality as far as I can tell, but I couldn't afford that set up. If you can, they really are nice and worth it. Maybe when I get to my 4th iteration I'll be there, but it is going to take a lot of lottery tickets and scratchers.