I can add to that, that I switched from using mangocam.com for a cloud dvr, to using a Lenovo ix2 NAS (Network Attached Storage) for my camera storage. There are two apps that are available for that series from Lenovo, but they are only compatible with the Axis cameras, and Panasonic, and a couple of others.
So any IP camera that is not on the list for Mindtree secure, or Axis, you are stuck using FTP to load the images to the NAS. I had to play around with the motion detection settings on all three of my cameras, due to two of them were getting to the point that they had uploaded over 32gb of data. Figured out what was going on, and got it down to around 400mb of data a day.
I would still if I ever get around to it, use Blue Iris, but that will mean running a dedicated machine for it, which I got rid of our old desktop, because I never thought of keeping it, so later on, may go with a small form factor or all in one unit, to run Blue Iris, if I end up wanting more features, but right now, just uploading any motion to the NAS is working.
The unit is 2TB mirrored in Raid 1, and if need be, I can always change over to 3TB drives if needing more storage, but right now I am set with what I have.
As for motion sensors on an alarm system, since the OP uses a non-monitored system, really it is no better than no unit at all, because the police are not going to respond to you calling them, telling them that your alarm on your home went off, unless you have video proof of a live feed, when you get the alarm, so with ddawg's suggestion, the two together work better.
But personally a dog is the best alarm system you can have. Our neighbors have stated, that when a vehicle pulls up in our drive, or the neighbor to the North of us, which their drive is within two feet of our house, our Golden goes nuts.
We also have the neighbor across the street has a German Shepard, who parents are retired police dogs, and he will even go nuts, if someone enters our drive, or is even parked in front of his house.
As they state, alarms and locks only keep the honest people out, and are only as good as the person who installed them, and uses them.