The longevity of a wax is MOSTLY affected by the number of hours the waxed surface is exposed to the sun.
If you park your car in a garage at home and at work, and it rarely sits exposed (except for surface parking when shopping and eating), a waxed surface can last for a year if the car's exposure to direct sunlight is extremely limited.
If your car is parked outside all the time, expect most waxes to last about 4-6 weeks.
My Honda is parked indoors all the time. I LOVE Collinite #915. I think it's the best all around wax they make. I wax my car 2 times a year. It's all it needs.
But my wife's Subaru is outside ALL THE TIME, so unless I want to wax her car every month, it's pointless. This past spring, here is what I applied:
After some polishing, I applied a lay of Sonax Polymer Net Shield, and then a layer of ReJex. After 2 days of cure time for the ReJex, I applied a coat of Collinite #915. The Sonax will provide the protection, the ReJex was applied to protect the Sonax, and the Collinite was applied to slow down the deterioration of the ReJex.