Valve adjustment is typically every 3000 miles. I usually drive less than that each year and I adjust the valves and change the oil at the start of each driving season in Michigan.
When you adjust the valves you will need to know if you have steel or aluminum push rods.
And you can tell which ones you have with a magnet. I suggest watching numerous YouTube videos regarding the process. It is very easy to do, just remember to adjust the valves with the engine cold. Don't start it to move it into position or anything. Set that up the night before if you need to. After you adjust the valves run the motor for a few minutes to warm the oil then change the oil. Annual maintenance is now complete.
I always check air pressure before each drive. It's best to run it lower than the recommended psi listed on the sidewall of the tire. The car is very light, especially the front end, and correct tire pressure is vital to a comfortable ride. PSI for most runs between 18-22 in the front and 20-26 in the rear. I usually ran 18 in the front and 22 in the rear and my car rode quite comfortably and it handled very well also.
Every other year or so add some grease to the front beam using the Zerk fittings.
There really isn't a lot to maintaining the car but don't ignore it either.