Wireless and quality don't go together.
3 bed semi - so
kitchen, hallway, dining room, Living room - that's 4 PIR's. Kitchen door - that's a mag contact\Viper. Living room window should be another Viper as should the kicthen window. Upstairs hallway another PIR.
That makes a total of 8 sensors\zones. Although you can fit the kitchen window in series to the kitchen door and the living room window in series with the living room PIR. You should have 2 Panic buttons - 1 upstairs and 1 downstairs, ideally in the hallways. These can be in series.
That makes 7 zones in use, with 1 spare - assuming the panel is 8 zone.
Texecom make good panels and PIR's and a strobe\bell. Vipers are made by Honeywell.
Annual service - that means popping the cover having entered the engineers code and checking the battery voltage, whilst it's connected and again with it disconnected. Never seen an alarm "engineer" doing anything else on a domestic system.
Perfectly within the realm of a competent DIY'er to fit. The Texecom range of Veritas panels allow the easy connection of a phone\text dialler.
Only thing you need to be prepared for is lifting some boards upstairs and perhaps a little re-decoration downstairs\upstairs depending on the runs required for the cable. Best to use 8 core alarm cable, even tho 6 will do. For future upgrades, should you replace the panel or upgrade to one that can cover the shed\garage.
Panels are available with a greater nbr of zones and far more functionality, i.e. split the whole property into say 4 areas, can arm\disarm all areas, or just some areas whilst not others. Each person can have a separate code, that you can dictate what they can and what they can't disarm. Plus master code (not to be confused with engineers code). also can dictate what remote keypads can arm\disarm. With these you aren't limited to a small number of sensors\zones - you can have several sensors in each room - i.e. PIR, windows sensors and another on a patio door. Even have it send you a sms if a sensor has been triggered and it tells you which one triggered - i.e. each sensor is given a textual name. You can then reset remotely via a registered mobile phone. Depends what you want to pay.
Also with most domestic systems - it will only trigger when a burglar is physically inside the room, which might be a little late by then. Better to have it trigger when they try to force the window or door but aren't yet inside.
HIH
Dibs
p.s. PVC doors - make sure the locks are snap proof locks and also fit door jammers to the frames to stop a door being brute-force.
