LIFESAVER

I deliberately spent a little more money for a smoke detector because I'm afraid of a false triggering / false alarm. If the smoke detector beeps and no home is, the neighbors call the fire department, these gains an access to the apartment and is addressing damage to. At best, only the door cylinder is drawn.
To minimize the possibility of such a case, I spend some more money for smoke detectors.

The smoke alarm makes a very high-quality impression, absolutely no comparison to a cheap DIY lights for 3-5 Euro. The processing is error-free. The seat in the detector base is entirely appropriate. My first impression is very positive.

Battery:
Only when the detector is in the socket, the battery is activated by a small microswitch. Thus, the energy of the battery is not already used up (shop, warehouse, transport)

Caution:
Make sure that the smoke detector is mounted at least 50cm away from the wall. Otherwise a correct function is not guaranteed.
I've seen people put the smoke detectors for optical reasons in a cabinet -> Of this I can only advise! The smoke always collects in the event of a fire in the ceiling. The smoke detector is not located directly under the ceiling, the triggering of the smoke detector is delayed unnecessarily long. Until the smoke reaches the limit smoke detector.

Conclusion:
Think about it again after - is your reliable smoke detector not some extra money worth it?