Bro arsenal, no need for the heavy gear, just household items can help to secure. The people of old Singapore, used broken bottle glass to put on top of their walls. Decorative yet strong deterrent to would be climbers. Empty soda cans, etc can be your first layer of defence as they act as noise makers should intruders.
There are also caltrops that one can buy or make oneself to scatter in susceptible areas should one need to be away for a long time (but then please remember where they are when you come back!!)
Never underestimate the value of cheap alarms. Yes cheap alarms though can be defeated easily, they can be augmented with more of them as each will add to the noise and length of time taken. I remember back in the past, someone liked to open my cupboards.
I scattered 4-5 of those toy mini grenades with a red explosive cap (only makes noise) on it and put them carefully inside the drawers and cupboard. Imagine their surprise when they opened it. Of course i was alerted to it as well and came strolling in. The person tried to close it and activated the last remaining one.