baby monitor question

Priscilla
Thoughts on baby monitors?
We recently got a new apartment with two bedrooms. The rooms are side by side, and our 3 month old slept in there for the first time last night in his newly built crib. Well, I'm sure he slept all night, but there's a small fear of " what if We didn't hear him " 
My SO and I have a irrational fear of baby monitors due to scary movies.