Used Toyota cars have high reputation on the durability, now nealy 80% of Toyota cars sold in last 20 year are still on the road. That kind of durability translates into significant long-term savings. Toyota knows how to build vehicles that last, especially the engines.
Toyota works deeply on their engines so as to increase reliability and longevity. Toyota comes in the list of those companies which do R&D on their engines so as to make their engines better and everlasting and they are constantly looking for ways to make their engines even better, which inlude high-quality materials, precision engineering, conservative design, rigorous testing, regular maintenance, etc.