At an event in Berlin, the LKA described video, alarm systems, and dogs as ineffective, at least as protection against burglaries, not for the family's sense of security.
This was presented in a similar way in a police lecture at a real estate fair in Osnabrück. First of all, one should invest in mechanical security for the weak points (windows and doors, especially those not easily visible). Of course, also pay attention to other things that don't even have to cost anything (not leaving ladders in the garden, removing climbing aids, making the property visible, being mutually vigilant in the neighborhood, etc.).
I have also followed the additional advice to install lighting (motion detectors with LEDs around the house). This can be deterrent, especially if the offender faces the risk that neighbors might become alert. So windows should be within sight, allowing observation.