I'm getting my BTO keys soon, should I exhaust all savings in my OA?

Keep $20,000 in our CPF OA because

1. the 1st $20,000 earns an extra 1% interest so you are getting 3.5% for OA. Not bad.
2. a buffer of $20,000 allows you to cater for emergency payment if you suddenly get retrenched / unemployed
3. This buffer can help in accommodating for higher interest rate from the bank that is higher than your monthly contribution from work (I encountered this last year)

Seedly has a good article on this CPF hack- https://blog.seedly.sg/cpf-hacks-tips-for-singa...

No. It's prudent to keep an amount (20k for current rules) as it helps you to plan finances and tides you over unemployed period, so you can focus on getting a job.

The interest in CPF is 2.5%, which is really only prudent to pay off if the interest for your bank loan is hitting 2.7% or higher (which in this case, just paying off might be a better choice, which you also need to take into account the refinance and other fees).

EDIT: I saw many posting on that extra 1% interest. Its only applicable if you have less than 60k CPF combined (including OA). Once you have 60k in SA and MA, it doesn't matter how much you have in your OA. Hence i said just to keep enough to pay for 1 to 2 years mortgage.