It is not worth it
Worth means value. If something is of great worth, it is of great value or importance.
- A college education will be of great worth to you later.
If something is worthless, it is useless.
- His ideas are usually worthless.
It’s not worth it
Used for saying that the value of something does not justify the concern you are showing.
Sona: Should I get this coat dry-cleaned? The stain isn’t coming out.
Akhil: It isn’t worth it. I only wear it when I work in the garden.