There are many schools of thoughts regarding paying up your loans for your housing. This post serve as a summary of what I heard about what people did with their HDB housing loans of 2.6% p.a.
(1) Should borrow as much as possible since it is only 2.6% p.a. It is the cheapest and safest loan around. If one has extra money, should not pay up, should use it to get investment return of greater than 2.6% p.a.
(2) Should pay up as soon as possible. Pay whenever you got lump sum so that you can be debt free as young as possible. A debt free person is a carefree person.
(3) Should pay up with anything in excess of 20k in your CPF OA account. Base on current CPF rules, you will earn 3.5% (2.5% + 1%) for the first 20k ......