The problem with buying used is getting cars that have actually been properly maintained. Used car lots will bondo over everything, and paint over rust on the frame. Anything to hide everything they can. The best cars seem to be retired seniors. Estate sales, or just giving up driving. They are often single owner, single driver, aren't abused, low mileage for their age, only get driven in good weather, and are well maintained.
Leasing is for people that don't drive much. The dealership wants the car returned in perfect condition, and wants it returned with low mileage (because the depreciation is non linear and they want to turn around and sell it for a profit), and as such, the fees you will pay for driving a lot with a leased vehicle are quite large. From a strictly financial standpoint, if you drive a lot and still want new cars, you are far better off buying, and then trading it in, or just selling it yourself/through a broker.
The best choice is again, buy a gently used car, and run it till it's not quite in the ground. If you could effortlessly buy and sell the cars, you'd buy a bit later, and sell a bit sooner, but you can't generally do that, so pay a bit more for something less used, and run it a bit longer.
Whatever you do, make sure you buy a reliable vehicle. A 10,000 dollar car that has a total running cost of 40 cents a mile is worse than a 15 thousand dollar car that costs 25 cents a mile if drive it even 35,000 miles. There's general fuel costs, but things like the prices of oil changes, new tires, windshield fluid, wipers, brakes, etc all factor into the long term costs of the car. Insurance counts too. An SUV is not only a vacuum for gas, but the chances are that it takes much bigger and more expensive tires. That can easily be 2 or 3 cents per mile by itself.