The first question is how sophisticated an alarm system do you actually need. This, once again, goes to what you are trying to protect. If, from a jewelry standpoint it's a relatively small amount then a more basic system is fine. If you are trying to protect a lot of stuff including jewelry, artwork, electronics, etc. it's better to have a higher end alarm system.
A basic alarm system will usually have sensors on doors and windows that will trigger an alarm. Add motion detectors in and the system is much more reliable (albeit problematic if you have pets). Add cameras and you are going to have more protection. Add things like motion sensitive cameras, digital recorders, etc. and you're dealing with a jewelry store quality system. The alarm system world has been growing by leaps and bounds lately as the technological advances have made things possible that never were before, both in terms of recording incidents and notifying people (since everyone now has a cell phone). Again the more you have to protect, the better system you'll need.
If you're are concerned with personal safety as well you will need things like panic buttons and you will have to make sure you have a system that will allow you to be in the house with it on. The problem with these systems is that you need to remember about them constantly as you can set them off by accident quite easily. And if you make too many mistakes in setting them off, you tend to stop using them regularly and then you're right back where you started. So if this is something you want your system to incorporate you need to think long and hard about how careful you are going to be in using the system. And again, if you have pets, or kids, these types of systems get vastly more complex to use and stay on top of.
There are, as I said, great advances being made in the security world. Here is a link to an alarm system using your iPhone: https://www.ismartalarm.com/ that has raised its funding through a crowd sourcing venture but looks like it would be an excellent reasonably priced alternative for someone who wasn't trying to protect a lot of stuff and wants to be able to control their alarm system themselves.
One other note. Most alarm companies give you a sign to put up outside your house saying that the house is protected by their system. The thinking goes that if the criminals know you have an alarm system they will be less likely to try to get into your house. (The alarm company has the additional thinking that it is a great, and free, way to advertise.) I am of two minds on this topic. The first is that when you put a sign like that up it immediately says "I have something valuable to protect" and will make you more of a target. On the other hand criminals tend to look for the easiest opportunities and the more barriers in their way, the better you are protected. I think using the signs depends somewhat on where you are located. If you live in an obviously expensive area, the criminals are going to know you have valuables and you might want to use the signs. If you live in a dangerous part of town, it will also help as you want as many barriers as possible. On the other hand if you live in a somewhat typical middle class neighborhood, it might just draw the wrong kind of attention.
Next article will be on insurance which is the third (and sometimes most important) part of jewelry safety. The rings pictured above are some of my 18k yellow gold wedding bands.
