To want a burglar alarm?

[NiteFlights]

DH and I recently moved to a big house which is a total renovation project. We have work going on and there is somebody here pretty much all day every day, but at night the house feels quite vulnerable. We have plans to double glaze and put shutters on the downstairs windows but not yet, as we have prioritised our budget to do external work, heating and plumbing first and then save up before the next phase.

I have had a quote from ADT of around £600 plus £30 monthly for an alarm, which is a lot of money. I know the reason they are pricy is because they are monitored. I think I would feel safer with one of their boxes on my house than a DIY alarm, even though the actual alarm would be similar. Their website makes much of the fact that ex-burglars say burglars don't burgle ADT alarmed houses. I want to believe this!

I need to discuss this with DH, but before I do, can anyone share their experiences? Especially opinions of ADT? I am generally quite brave about this sort of thing and am usually quite happy being alone, but I have suffered from an anxiety disorder in the past and I am starting to be slightly concerned about myself - e.g. last week one night I literally couldn't sleep until about 4am as it was windy and everything was crashing around making me fear intruders every half an hour! AIBU to spend quite a big chunk of our budget to make myself feel safer?