My suggestion is the next time you move, look for an apartment with no portero. I know there are more good ones than bad ones out there, but how are you supposed to know which is which? And it was good to point out that perhaps it's not the portero but someone who gets ahold of his keys - no portero = no extra keys lying around. ONLY 1 out of at least 50 break-ins I've been told about over the last 5 years happened in a building that doesn't have a portero. So yes, of course it can still happen, but your chances are much slimmer. That's my advice, and I can guarantee you that for as long as we are here, we won't be living in a building with a portero. In 5 years I've never had one, and I've never felt the need. Oh and not to mention - your expensas are around 75% less!