Leasing car vs financing

I asked this 10 months ago, I just want to be able to formulate a better argument. I am in the process of getting a new car right now and my stepdad called me and kept going on about how leasing a car is the "smartest" choice. He cited that there is no headache when trading it in, you get a new one every 3 years or so and can renew the lease if you like it. I told him that, unlike leasing, if you own it you can sell it off eventually, even if it is a depreciating asset.

He kept asking how I don't understand why the leasing is so much better, but chose to not listen to my side of not trying to show off and not really caring about rolling around in a brand new car every three years. I just care about reliability and want my money to go a bit further, especially since I started earning more than I have before. How can I articulate a proper argument so he calms down and stops pushing the idea?