Chains? Alarms?

A big chain? More locks? An alarm system?
What to do about stepping up security on my side of the hill here?
I've been trying to be nonchalant, and grown-up, and all good things about being robbed here while I was asleep alone. But truth is, I have been a bit spooked by it.
I find myself sitting here in the evening with the iron grates shut -- even while I'm here. I've hardly sat out on my terrace. And when I've come back late at night, now I'm hoping to find Nero, the Roman emperor dog next door, barking his head off, instead of wishing he'd just shut up already.
My carpenter came up this morning to look at what he could do to make me more secure. He's going to put a big bolt-like chain on my front door so I can lock myself in better at night -- and of course replace the lock on the door that was broken into. (The iron grates still work on that door, so I've had them shut anyway).
He wants me to get an alarm system though.
A friend of mine here who has one says she never uses it because it's complicated and so sensitive anything makes it go off. But her reasoning is that it deters robbers just because they can see that it's there. Okay, I can see her point.
I went to another friend's house for dinner last night -- an elderly woman who lives alone further up the hill here. She didn't seem worried about robbers at all -- her gate wide open, no iron grates on her windows, and all alone there often, in a much more isolated location than me.
She said she's had two pairs of binoculars stolen there over the years. That's about it. So she doesn't worry about it too much. She doesn't have a lap-top though.
Maybe that's the key. Not have anything.
I can see what it is they want -- electronic things they can sell quickly, like a lap-top or a digital camera. And any cash you may have lying around.
When I'm not here, I don't worry about it. I can see there would be nothing in here of any interest to any robbers.
So it's just a matter of divesting myself of anything while I am here, I guess.
Or invest in some monster alarm system.
People tell me that once the robbers have come, that's it. They don't come again. Then others say that sometimes they come back soon after, after they think you've replaced what they just stole.
I'm not sure what makes most sense. I wish I didn't have to think about it.