There can be a number of reasons you have flickering lights. Your lights might flicker and get brighter, dimmer or both may occur. The cause can depend on whether one light flickers, a group of lights on a particular circuit, all the lights in the house at the same time or perhaps your neighbours lights are doing this as well.
If it’s just one light fixture, it might be something as simple as a bad light bulb. In fact it might be a bad connection between the light bulb and its socket. If it’s a group of lights on a particular circuit, then it could be that connections are not tight.
They might flicker when a large appliance turns on like an air conditioner. This may be caused by the large draw of power when it kicks in.
If your neighbours lights are doing the same thing, it may be that you need to contact your local utility to source out if something is amiss at the street.
Naturally, all wire connections should be tight however a common cause of this is a loose neutral wire. With a neutral wire connection that is loose it can become very hot, overheat, and cause an arc, damage or even a fire. It can also be a shock hazard. Don’t ignore lights that flicker in your home…call a professional to get help.