Days? Either you live in Buckingham Palace or you weren't trying too hard to find it.

We own a condo and our neighbors rent their place. Their fire alarm has been beeping for a full week and even though they've been by to fix it up they haven't done anything about it.

Remove that one unless it’s wired in from the AC power. The whole point of a smoke detector is to locate it somewhere it could actually detect smoke and not have a lot of false alarms. Inside a cabinet, it would be highly unlikely to detect an actual fire. That’s why smoke detectors are normally located on the ceilings near bedrooms and never in a kitchen or bathroom. When I was a boy our house burned down one night. It was a terrifying experience. I remember running out through a burning room with my Dad. This was before smoke detectors. The most dangerous fires happen at night when all are sleeping - That is the purpose of smoke detectors to give you enough time to evacuate the building. By the way even with replacing the batteries yearly, smoke detectors have a life and have to be eventually replaced.