[cheebacheeba]

Yeah the traps work, though not always.
"Places to hide" like clothes being everywhere could be a factor. You'd probably know if one was hiding out in/on your clothes because they piss on everything.
The snapper trap things will kill them one at a time, but then there's the initial outlay, constant refilling with food, and can sometimes be a grisly disgusting stinking mess that you would be most likely of all scenarios (short of eating their shit), to contract something...that and like I said if you have an infested building it's like trying to hold back the tide with a bucket...so, fun for a while to be sure, and might give a feeling of revenge but inefficient for the ongoing cause.
The electronic devices will keep them ouf of your apartment, or leaving soon after entry - this I would say is the most efficient method to keep your individual apartment rodent free, as most landlords/superintendents will not want to acknowledge the problem and/or blame you for it, will generally not act on an infestation or order/purchase a fumigation until it becomes "major", eg - seeing multiple mice on entry, which is MUCH worse than you want things to get.