Just started a new job. I am earning a 40k annual income. Understand that we can top up 7k to enjoy tax relief. Is it advisable to do so? Also, we have to top up 7k every year. Can someone explain more?

https://www.iras.gov.sg/irashome/Individuals/Lo...

The link above should help to explain a little. There are tax calculators to estimate the income tax payable. For the 40K annual income, you have to factor in your CPF contributions etc. So try using the calculator first.

https://www.iras.gov.sg/irashome/Quick-Links/Ca...

For cash top ups to CPF SA, it is under the deductions section. The tax relief will be on the income earned during the year of the top up. Meaning if your top up is this year, the relief will be calculated for the income tax payable next year. So yes if you want to get the tax relief you have to top up cash every year to your SA.

https://www.iras.gov.sg/irashome/Individuals/Lo...

Do note the tax relief is deducted from your chargeable income. Not against your income tax payable.