Between the age of 60 to 90 years old, a retiree would need $300,000 saving on standby.
Assuming the overall living expenditure is $10,000 a year, excluding CPF monthly payout.
If you are thrifty, spending $15 a day on food, either cooked food outside or cook yourself, is adequate, $10,000 would barely make it, but cutting corners, it can. Assuming that one, does not have old age diseases that require long term medication or periodical visits to specialist; it is enough. Your figure of $300,000 is reasonable, provided that the PAP raising GST, 4G or 5G salaries, utilities, medical costs...$300,000 will not be enough, at least $600,000.
The biggest cost one have to face each day, are indirect taxes, plus A VERY EXPENSIVE GOVERNMENT & A USELESS PRESIDENT, in which we have to pay indirectly, whether we vote for them or not.