What happens if CPF changes their policies which affects the current interest rates? Do you think there should be a ratio of how much you should place into CPF and keep as ready cash?

Though CPF seems a safe choice

possibly if applied ultra-longterm

excess money could better be put

into passive global or U.S. index

ETFs like tickers: VT, or VOO to

mention just examples

(at least the past performance

seems super-successful

compared to other asset allocation

choices like f.ex. bonds or mutual funds/unit trusts

Ready cash should be 6 months worth of expenses. No need to make it a ratio.