Does anyone have any idea on how to upgrade house security further? What do you think about security cameras?
Like you already said you should definitively get security camera's.
You should probably get a motion sensor one because then you won't have 6 hours of footage to look at.
If you really want that extra teeny-tiny bit of security you could also get a guard dog.
A guard dog is a thief his biggest fear. If your dog starts woofing it could alert the neighbors that something fishy might be going on in your house.
Guard dogs are in general pretty nice to their owners, Most of them don't bite and if you make the right choice you might make a extra friend
You could also get a alarm if a guard dog is a bit to much or you are allergic to dogs.
It also does the job of alerting your neighbors of any fishy activity.
I hope this helped at least a tiny bit.
I wish you the best of luck!