Do you want to make enough money to buy something? Or do you want to experience security by having a sum of money saved on your bank account?
If your goal is to save $20,000 a year, you should divide it with 12.
20,000 divided by 12 equals about 1667.
This means in order to reach your goal all you have to do is save 1667 dollars a month. If you do this every single month, you will automatically reach your goal.
Having money on your bank account is good because first of all it will grow with the interest rate, second of all it's always nice to know that if a big once-in-a-lifetime opportunity comes up, you have the money for it. Third of all, having money saved is something expected by adults.
Now, 20,000 dollars might not be the most optimal goal for everyone. If you don't have enough money to save after your expenses you might have to look at a smaller goal. But even if it's not big money being saved it's a really good habit because when you make more in the future you'll save that money out of old habit.
And remember, there's always ways to make more money than you currently do.