There are several ways that HDB (Housing and Development Board) owners in Singapore can preserve their profits through careful planning. Some strategies include:

1. Renting out a room

HDB owners can rent out a room in their apartment to generate additional income. However, they must comply with the HDB's rules on renting out rooms, such as obtaining the necessary approvals and registering the tenant with the HDB.

2. Upgrading the unit

HDB owners can renovate or upgrade their unit to increase its value. This can include simple upgrades such as repainting or installing new flooring, or more extensive renovations such as remodeling the kitchen or bathroom.

3.  Selling at the right time

HDB owners can maximize their profits by selling their unit at the right time. This may involve timing the sale to coincide with a market upturn or selling when demand for housing is high.

4. Keeping the unit well-maintained

HDB owners can also preserve their profits by keeping their unit well-maintained. Regular cleaning, repairs, and maintenance can help to keep the unit in good condition and attract potential buyers or renters.

5. Seek professional advice

HDB owners can also seek advice from professionals such as real estate agents, renovation contractors, and financial advisors to help them make informed decisions about how to maximize the value of their property.

6. Lease buyback scheme

HDB owners who are aged 55 and above can sell a portion of their remaining lease to the government and continue to live in their flat while receiving an income from the sale. This can help to increase their retirement income while still being able to live in their own home.

7. Rent out the entire unit

HDB owners can also rent out the entire unit if they are eligible to do so. This can generate higher rental income than just renting out a room, but it also means that the owner will not be able to live in the unit while it is being rented out.

8. Invest in property nearby

HDB owners can also consider investing in property nearby, such as private apartments or landed property, as a way to diversify their portfolio and potentially generate higher returns on investment.

9. Consider the resale market

HDB owners should also consider the resale market and the demand for their type of unit in their area. For example, units near MRT stations or in popular neighborhoods may fetch a higher price than units in less desirable locations.

10. Plan for future

HDB owners should also plan for the future, such as considering how long they plan to live in the unit, whether they will have enough retirement income, and whether they will need to move to a different type of housing as they get older. By planning ahead, they can make more informed decisions about how to preserve their profits.

It's important to note that different strategies will work better for different people, depending on their individual circumstances, so it's essential to carefully consider all options and seek professional advice as needed.