In security terms, a visibly poorly maintained piece of equipment can tempt burglars rather than warn them off.
Does your external bell box — the burglar alarm sounder on the outside of your house — look like the one in this photo, or even worse? Do you think it's still a deterrent against burglary?
For a start, it doesn't look like it has been maintained at all. The access screw is rusted through, the battery inside has almost certainly died long ago, and the alarm system behind it has probably seen better days too. Just as importantly, there's no visible sign the alarm might actually be working — no LEDs, no external indication at all.
Now picture that bell box in a row of houses with modern, clearly working sounders on either side. It isn't a deterrent any more — it's a signpost. A burglar is far more likely to pick the house without a visible working alarm, and a dead bell box says exactly that.
So if your bell box looks old and outdated, don't ignore it. Have your current intruder alarm serviced and brought back to life, or better still, have a modern intruder alarm system installed — one that visibly means business.