Is it always good to have a lot of money in your CPF?
Maybe, maybe not!

As the amount of money in your CPF account increases, the amount of interest you get from CPF increases.
However, the effective interest rates you are getting from CPF also decreases.

What is Effective Interest Rates?
Effective Interest Rates (EIR) is the total interest you are paid on the total amount of money you have.
Eg: Total CPF Interest for the year divided by your total CPF balance (express in percentage).

For money in your Special, Medisave & Retirement Account (SMRA),
a) each account will earn a 4% interest on its money
b) first $60,000 will earn an extra 1% interest
c) those age 55 & above will earn an extra 1% interest on the first $30,000

Below is how the interest curve will look like

Before age 55
The first $60,000 in your CPF will earn an interest of