For people to be able to offer advice/suggestions to help you, you need to say what kind of retirement lifestyle you aspire to.

As an example, my wife and I, when we retire, we want to continue living in our wonderful condo. We want to continue having a maid to do the housework and cooking, a reliable car to drive around, occasional dining in restaurants, attending concerts and live musicals and overseas holidays. Simply put, we want to continue our current lifestyle. And we know the cost of such a lifestyle ~ $130k -$150k pa. Factor in 3% inflation and estimate how many years you expect to live in retirement and you will get a projection of the amount you will need for retirement.

In our case, our "number" came up to $3.5m in today's dollars. To achieve this figure (not including our primary residence) we have to work till we are 58.

So if you envisage a simpler lifestyle in retirement, eg living in a HDB studio, no maid, no car and no holiday abroad, I think the payout from the CPF life annuity plan of $2400 per month total for both you should be just enough. But to be safe, it is good to have a little saving somewhere to handle emergencies.