buy new, full warranty, trade it in, get another one, rinse, repeat..still cheaper than insuring old crappola.
You can continue to buy new, trade it in, buy another, over and over if you wish. There are certainly positive aspects to that approach, but thinking you are spending less money that way is ludicrous.
New vehicles are the largest ticket item you will likely ever buy that depreciates. The average vehicle will lose over half its value in the first 5 years of ownership, most people are financing them during that time as well. Meaning finance charges AND full coverage insurance.