Same in NL. Sirens are only turned on in the most extreme cases. In most cases lights seem to be enough. I do get the impression that firefighters are a bit more likely to use sirens than police and ambulance are, but I'm fine with that.
this is absolutely not the case in Amsterdam. 90% of ambulances/firefighter cars have their sirens on full blast. this is especially noticeable in summer nights when they can be heard from quite far away
