Search local companies first. Not sure which ones would be in your area.
A salesperson can come to your home and give you a quote as to what it will cost to install the system. Get quotes from multiple companis. Also when comparing companies thing to keep in mind are: Monitoring fees, service calls (how much per hour), if a contract is involved and if one is, how long you would have to sign for.
If you want the monitoring not just the system alone (which I highly reccommend getting the monitoring) find out how many operators are working each time. Smaller companies only have one Monitoring Operator on at a time and you don't want your fire alarm to be put on hold cuz he/she was in the bathroom going pee. Lol, sounds silly but its something I consider.
As for equipment not breaking, well things do get old or stuff happens. When it comes to smoke detectors vacuum them out one in awhile. Getting any dust in them can cause them to be less sensitive, cause them to false and also cause them to plain out not work. Also if you have any critter problems in your home such as mice they'll sometimes chew wires which can result in false alarms or troubles on the panel. I've seen this hundreds of times. A wire gets pinched or chewed and we (the monitoring station) receive a trouble alarm and a technician ends up going to the persons house to fix it at about $60/hr plus tax.
Also watch out for silly deals. I've gotten lots of calls at home from companies trying to install a system for free. Sounds great but the problem is they'll do it for free if you sign a 3 year contract and its just a few devices. Few devices meaning one or two doors protected with one motion detector. Which is BS because most people have at LEAST 3 doors in their home (garage entrance, front door, patio door) and want a motion in each room. Glassbreak detectors are also good to have. They'll activate if you drop a glass plate for example near it but I've personally never seen one false. Motion detectors and door contacts do false, get old, wear down, go out of alignment.
Hope this helps! Anything else you want to know or if you have any questions feel free to e-mail me from my profile page.