The answer to 'skylight worn out' is that a skylight can become worn out over time due to exposure to the elements, such as UV radiation, temperature fluctuations, and weathering. Common symptoms of a worn-out skylight include leaks, cracks, fogging or discoloration of the glass, and difficulty opening or closing the skylight.
The best solution will depend on the extent of the damage, but may involve repairing or replacing the skylight. Minor issues like cracks or seal failures can sometimes be fixed with sealants or replacement parts, but more significant damage may require a full skylight replacement. In many cases, it's best to call a professional roofer to assess the damage and recommend the appropriate solution.