You don't need a sparkie for like for like replacement anywhere, only for modifications.
A problem that does occur is nuisance tripping caused by appliances, they are not as such faulty, but the earth leakage can in some cases exceed 30mA. Common issues are kettle/cooker/washer elements, starter capacitors in motors and flourescent fittings.
The greatest risk is, as I commented earlier, the use of equipment outside the house in fact with some earthing systems RCD's in this case are mandatory for all suppies (sheds, garages) outside the house.