We will state several reasons of electrical failure or reasons to get professional help.
Electrical Lighting and Switches; A worn out bulb is easy to fix however there might be instances where the switch or the bulb socket will be worn out too. There are various reasons for electrical lighting failures aside from worn out bulb it might be due to a wrong wiring used in the first place sometimes the type of wiring used for switches and lights have specifications to allow maximum electrical output and reduce heating on the wiring itself that might cause damage. There are also moisture sometimes the walls or ceilings will develop cracks or fatigue due to changing weather conditions and also by the aging too and that might weaken the electrical wiring or cause the bulb socket to be damaged when moisture gets in and this is also dangerous if moist happens because if you are unaware of it, it could cause grounding you. So best in severe cases and if you know that fix is beyond your capability call for professional electrical repair help.
Electrical Wiring and Rewiring; there will be a time where you will need to rewire or install a new wiring system in a room or in the whole house. For example adding a new air-conditioner unit, an air-conditioning unit must have its sole outlet for use and that outlet cannot be connected to other wiring that is also being used by other appliances. If any other appliances or devices are attached to the same wiring line of the air-conditioning unit it might cause a huge fluctuation in the power on that line when the air-conditioning unit starts running. The conflict might cause the other appliances to be broken down and it might also damage the circuit breaker causing you money for repairs. Thus it is best when you need a new wiring line or rewiring an area on the house its best to call for electrical repair professionals or technicians because that is their job.
In any cases any electrical maintenance or repair must be done by professionals only unless they are only simple fix like replacing a light bulb which you can do yourself but if in times you know and must know that the case of electrical repair, wiring or maintenance is of extreme and out of your capability do not hesitate to contact a reputable electrical repair company immediately, not only it will save you money but to protect you from potential risks and hazards too.