the middle light doesn't burn out the two outside lights do
Flip off the vigour to the sunshine. Do away with the screw that holds the sunshine meeting in position. Pull the sunshine fixture up and out. There's enough light cord rolled up within the niche for the fixture to arrive the deck. Now you may have access to the light. Unique light producers use exceptional methods for attaching the lens assembly, but it surely must be self- evident methods to open it. Substitute each bulb and gasket. Take the historical gasket with you to the pool retailer because there are very many specific ones. Reassemble and reinstall. Executed!
time to replace the fixture
The two keep burning out due to excessive heat. The metal base in the lamp (bulb) socket might be loose. There might be a glass shade over the lamps causing the heat to build up. The wattage of the lamps might be higher than the mfr recommended wattage. There are many reasons, but it will definitely be due to heat.
There are many reasons why light bulbs burn out prematurely. We have experienced this in our lamp shop for many decades. When this happens repeatedly there are several things to consider in addition to the valid ones which were covered in Dave's answer. Here are a few others to consider arranged by how frequent they might occur. 1- If the light bulb is not securely screwed into the socket, it could cause an electrical short which will burn out the bulb quickly. We see this problem very regularly. 2- If a small voltage spike is the problem, you may solve this problem by purchasing higher voltage bulbs (not higher wattage). In the USA, many standard light bulbs are rated 110-120 volts. A heavier duty bulb rated 130 volts may last longer. 3- There may be a voltage spike in your electrical circuit. A small voltage spike is very common and expected. But abnormal spikes do happen and they will blow out light bulbs. This is a job for a certified electrician who can conduct tests to determine if this may be the culprit. Good luck with your fixture.
