If someone is retiring in Jan 2018, how much does he need per month? Let's assume his
HDB flat is paid up, he has no liabilities, no dependent and he leads a simple retirement lifestyle.
Food = $4 x 3 meals x 30 days = $360 pm (eat at hawker centre or cook his own meals)
Utilities and other household items = $200 pm
Mobile phone = $90 pm
Public transport = $50 pm
Medical fees and insurance = $500 pm
Entertainment and misc = $100 pm
Holidays (pro rated) = $200 pm
Total = $1500 pm or $18k pa
He needs to take into account of inflation which is about 2% pa. So the following year, he will spend $18.4k pa. This is a simple retirement lifestyle which is good enough.
Rich people who wants a super luxurious retirement lifestyle - retire in a bungalow with swimming pool, eat at high end restaurants every day, travel first class, stay in 6 star hotels, drive a supercar, etc, they will need a lot of money to retire. They may need at least $50k pm of expenses.
Whether $1.5k pm or $50k pm of retirement expenses will depend on each person's affordability and choice.