Surveillance

It occurs to me that I am sorely lacking in Surveillance equipment; a major protective element especially in a fortified compound. Since a big part of defense against zombies maintains that you are ever aware of their presence, surveillance equipment seems most necessary.
By surveillance, I do not mean cameras, complex electronics, etc. Although these would be a nice addition to a fortified compound, and certainly come with certain compounds (schools, malls, etc), I am referring to more low tech surveillance, such as binoculars, or for the more prepared (and perhaps financially well-off) individual, night-vision goggles (page 101).
Oncoming zombies can be detected most easily through sound, but this should not be the only means of detection. With binoculars, oncoming zombies can be spotted (and dispatched, depending on your sniping skills) long before their moans are heard. The bonus to early disposal, is that the dying/dead zombie is less likely to draw zombies to you.
I believe that I do have a pair of binoculars somewhere; they shall soon be added to my anti-zombie defense kit. As for the night-vision goggles... they will have to wait, until I have more cash, or the apocalypse.