The answer to 'when to replace lighting installation' is that you should replace your lighting installation when it is no longer functioning properly, is outdated or inefficient, or when you want to upgrade the look and feel of your home. Lighting fixtures typically last 8-15 years, but this can vary depending on the quality, usage, and maintenance of the fixtures.
Some key signs that it's time to replace your lighting installation include flickering or dimming lights, frequent bulb burnouts, outdated or mismatched fixtures, and poor lighting coverage or quality. Upgrading to more energy-efficient LED lighting can also be a good reason to replace your lighting, as it can save you money on your energy bills in the long run.