B Harvey's comments (Letters, October 4) about the cost of intruder alarms rang a bell with me (pun intended), what with the high cost of the initial installation and then the annual "maintenance" (£70-£80 to check it is still working - a matter which can be done easily oneself by setting it off).

Why not do as I did, both for myself and for family and friends? Buy one of the excellent kits available on the market and, with help (two instead of one more than halves the time involved), do it yourself.

It really is a simple job. The wiring diagrams provided are excellent and readily understood and most makers provide a helpline, too.

The cost of buying a kit obviously varies depending upon the size of the installation but will be around less than half that charged by the companies.

With an ordinary three-up, two-down house, you will have the job finished in two days.

Go on, have a go. It isn't at all difficult.

-J E Bartlett, Upper Shoreham Road, Shoreham