About 3 years ago a large branch (about 8" diameter) from an old overhanging tree fell right on the transparent sunroof cover and shattered it into a million pieces. After picking them out of the sunroof mechanism (which no longer worked after the impact) and the inside of the car, I covered the opening with several sheets of magnetized vinyl. Works great, never a drop of water inside since then and it's stayed in place without any attention. Temperature control inside the car at rest or while driving at highway speed is like it was before the damage.
Being old now I never go anywhere since I can get stuff delivered. About every 3 weeks I go out and the car starts right up, I drive a 5-mile loop to circulate the oil and then park it for another 3 weeks. Been doing this for years. I do get an oil change annually.