The SRS is a perfect tool to use for retirement funding between 62 to 70. In the early retirement years when we are physically still active, we can use the additional funds to pursue interests such as travels, hobbies, get togethers, etc before really gearing down at 70. Thus, this is a perfect supplementary tool to CPF life which kicks in at 65.
If you stop working at 62, withdraw $44,000 per annum for your own use. Half of it is taxable which is $22,000 but this amount equals zero tax. $44,000 per year is very comfortable and gets better at 65 with CPF life. Assuming your funds should last 8 years, its best to accumulate $352,000 of funds in your SRS before you hit 62. Depending on the tools you use to grow the fund, one should be making voluntary SRS contributions of $15,300 every year between 15-20 years to achieve the desired amount.
Below are the brief description of tools you can utilise to grow your SRS savings.

Robo advisory investment:
Google Robo advisors and you get a whole lot of them ranging from the bank advisories to the young start ups. What are they? Instead of having human advisors telling you what funds, trusts or stocks to buy, the machine algorithms do the work for you based on your risk appetite and financial goals. For medium risk takers.
Bonds:
You can get stable and reasonable interest out of bonds. One can buy the Singapore savings bond or listed bonds on the SGX. Safest option will be the SSB which is guaranteed by the government.
Equities and Unit Trusts:
Simply link up your existing brokerage accounts with SRS or use the banks. Get invested in blue chips, reits , etc. This is high risk but high rewards, not for the faint hearted.
Single premium insurance products:
There are limited number of single premium annuities and investment products that you can buy. Check with your financial advisors. Tend to have a longer lock in horizon.
Fixed deposits:
For the risk adverse, structured or time deposits in local/foreign currencies with your favourite banks. I would generally not recommend this unless their interest is better than the bonds.
As with all things in life, try not to put all your eggs in a single basket. Good to spread them across different tools.