Burglar-proof apartment entrance door

Then rather have as few valuables as possible in the apartment and protect them somehow else (GPS) if possible.

You’re always wiser afterwards. ;)

The front door will definitely not be locked, which is why even a secure front door does not provide security. And someone always opens when the doorbell rings, according to experience...

I would reconsider that. In our owners’ association, it started with a tenant losing his keys, which led to a complete replacement of the locking system in the building. During the replacement, a transponder system was installed along with a motorized lock for the front door. That soon paid off. In the following years, three attempted break-ins at the front door were detected, which fortunately were unsuccessful. Shortly after we moved out, a camera was even installed in the entrance area for deterrence purposes. Ironically, one (!) day too late. The day before the installation, several high-quality bicycles were stolen from the underground garage. Luckily, ours apparently were not valuable enough. I was able to pick them up the next day when the cameras were installed as planned and bring them to the new home. My conclusion: as an owners’ association, invest some money and install a secure front door with a motorized lock.

Install an obvious weak point in the single-family house and secure it particularly well. For example, with a silent alarm (only with rapid security service or direct line to the police) or bear trap. I could also imagine a trapdoor into a cesspit. :p

I have experienced something like that. I was a weekend commuter. The following Monday the door was kicked in and the valuables were gone.

Occasionally all sorts of things happen, but basically you can’t just kick in a modern, "proper" apartment entrance door (not an interior door) with the RC1 standard and a proper frame. RC2 then increases protection against prying to about 3 minutes, RC3 raises that to 5 minutes with additional tools, etc.

That could only have been someone from the building. Who else would know that I’m not there every weekend?

Crazy, right? Here, twice in the 4th floor, someone took a bike chained up in the hallway, and twice a year in the basement the heavy metal doors were brutally torn open to steal some junk that was worth at most 5% of the damage caused; these were drunkards from the nearby garden shed association after their evening binge drinking, as was later found out. Against such blockheads you could install RC25, but eventually everything opens with brute force. The "ordinary" apartment and house burglar does not act so brutally and can be protected against more easily. If someone does come with a crowbar, drill, angle grinder, etc., that’s a different kind of burglar with a different goal anyway. In my opinion, it is always important to know exactly what you want to protect yourself against. Implementing all possible standards does not always help; an individual case consideration is always recommended here as well.

The unpleasant feeling lingers for a long time.

Yes. Exactly that is probably the most unpleasant part about this topic. The feeling that a stranger has been freely moving around in my private rooms is usually the worst thing; I know people who then couldn’t live there anymore and moved out or even sold the property.

But a locked door of course doesn’t help if it can be pried open with a screwdriver in a minute...

Therefore RC2 or a similar standard; then it takes about 3 minutes, which is already a long time with a lot of noise that most burglars want to avoid. Most of them..... Ultimately, there is no perfect solution here either; but I think you shouldn’t be led too much by fear and be sold all sorts of things that don’t necessarily help as much as you’d like. Still, I would consider what would make me feel best myself, because what good is a purely logical-technical decision if you still feel insecure. Somewhere in between there lies the individual ideal solution.

If I remember correctly, the only difference between RC2 and RC3 is the glass, right? Multipoint locking should already be standard with RC2.

We have an RC3 door, the only difference was the glass of the side panel.

In our former townhouse settlement, few neighbors were spared from burglaries or burglary attempts. Almost all during the day. At one neighbor's, they were inside while he was sleeping on the sofa. A good escape route, proximity to the highway and the Dutch border made the micro-location statistically top-ranked. We were spared, possibly because the big dog made the burglars prefer to go to the neighbor. Burglars don’t like noise. If you feel safer with burglary protection, buy what makes you feel safest – and add a loud alarm system. It doesn’t cost much, but from the outside it is poorly regarded in an attic apartment. With noise, most burglars disappear very quickly again and the damage remains low. A sticker saying "alarm secured" also helps, even if it won’t deter everyone. Most burglars are looking for a quick success. There are plenty of apartments. It is usually enough to make it more uncomfortable and risky for the burglar than many other apartments.