He is young, good-looking, and very rich.
In this sentence, should a comma be used before "and"?
Thanks in advance.

In most instances, it's a free choice.

The so-called 'Oxford comma (or serial comma) is recommended by some style guides and not by others.

In BrE, there is a slight preference to omit it:

He is young, good-looking and very rich.

Take a look here for some useful information, and watch out for examples when it's obligatory:

https://en.wikipedia.org/wiki/Serial_comma

PaulM