Have you ever been walking around B&Q on a Sunday and thought "Hey, these brushed chrome light switched will look great in the house", and then proceed to buy 15 to replace. You're saying "I don't need an electrician near me to come and put these in, it's easy".
You are right, it's quite easy to change a normal light switch, and I've made a how-to video on how to change a switch.
But, the danger is that most home owners don't connect an earth cable to the metal light switch as they don't quite understand the importance of it. I find so many switches without the earth connected.
If the earth is not connected and say, a live cable popped out of the terminal and touched the switch, the entire metal light switch would be live and you would get a nasty shock when touching it.
So, please always connect an earth cable to the metal light switch. Or, employ a professional electrician to do it for you.
We'd rather light the room up than you yourself!