Depending on the country you might not be able to do that. In some countries you have strict emission guidelines where cars older than 5 years need to be certified that they output emission below a certain threshold. It's good for the environment, but if you live in a place that has shit public transportation it can force you to get new cars and spend much more than required to have a car that suits your needs.
I have one car, it's 20 years old and I've had it since 2009. Sometimes I look around and think, maybe it's time to get one not covered in scratches with a dent in the back? But then I see posts like this and feel incredibly grateful this little banger has kept me on the road for so long.
You could always have your scratches and dent repaired, or learn to do it yourself as a fun hobby. (I'm not joking, by the way: I've done some body repair and painting on some of my cars, and it's kinda fun!)