Your 4-room HDB flat is already rented out to six unrelated tenants. Under the temporary occupancy relaxation, you could, subject to HDB approval, add two more until 31 December 2028. Do you take the extra rent, or keep the flat less crowded?

That is the practical question behind the extension announced by HDB and URA.

The relaxed cap applies to 4-room and larger HDB flats and private residential properties of at least 90 sqm in strata or lot area. Eligible private-home owners must register with URA to use the higher cap.

However, there are other conditions for HDB owners. For a whole-flat rental, a 4-room or larger flat can have up to eight tenants under the temporary relaxation. If you rent out bedrooms while continuing to live there, the eight-person cap includes the owners and authorised occupiers as well as the tenants.

But should you restructure your rental to fit eight tenants, and would that be the most profitable strategy?

Take a whole-flat 4-room HDB rental with six unrelated tenants paying $700 each. Gross rent is $4,200 a month.

If you add two tenants and reduce the rent to $650 per person because the home is more crowded, gross monthly rent becomes $5,200.

Under those assumptions, the uplift is $1,000 a month, or $12,000 a year. That's before any additional utilities, cleaning, maintenance, vacancy or reletting costs.

For an owner with a mortgage to service, that extra $1,000 a month could make a meaningful difference to the property's cash flow.

This is probably why the extension caught some landlords' attention in the first place. Why not make use of the relaxed policy and earn more from the same property?

But as good as it sounds to earn two more rental payments, you need to remember that you are also adding two more people to the household.

That means two more people using the bathrooms. Two more people using the kitchen. Two more people using the washing machine, air-conditioning and common spaces. More wear and tear. More cleaning. More chances of something breaking.

Not to mention, 8 people sharing a small space could easily create tension in the house.

Someone may complain that the living room is always occupied. Or a certain tenant keeps leaving a mess in the kitchen. Meanwhile, a different tenant always has friends over. And everyone can't agree on the air-con settings.

These things sound trivial until you, the landlord, are receiving all their complaints via WhatsApp.

Crowding can also narrow your tenant pool. If a comparable room in a less crowded home costs only a little more, some tenants may prefer the extra space and privacy.

That does not mean eight occupants will automatically lead to higher turnover. But any additional vacancy or reletting cost will eat into the $1,000 monthly gross-rent uplift.

That extra $12,000 is therefore not additional profit. Here is a more realistic formula to calculate your net benefit:

projected rent at eight occupants ? current rent at six ? additional running and maintenance costs ? expected vacancy and reletting costs.

Now after all the deduction, is the remaining margin still worth the additional management?

In any case, the higher occupancy cap offers flexibility, but it's not necessarily better to have more tenants.

The rules differ between whole-flat and bedroom rentals. For a 4-room or larger HDB flat rented out in full, the temporary limit is eight tenants. For bedroom rental, the maximum is eight occupants in total, including the owners and authorised occupiers, and the owners must continue living in the flat. A 4-room or larger flat may rent out up to two bedrooms. HDB approval is required before the tenancy begins.

For a private residential property of at least 90 sqm, the owner must register the property with URA to qualify for the higher cap of eight unrelated persons. Without that registration, the usual cap of six applies.

The decision becomes clearer once you stop treating eight occupants as the objective. Add the seventh and eighth tenants only if they still improve net cash flow after any rent discount, higher running costs, vacancy risk and the additional management burden.

And run the property on a six-person fallback. Under the current rules, the higher cap ends on 31 December 2028 unless it is extended again, so landlords should not build a longer-term rental plan that only works at full eight-person occupancy.

The number to optimise is not headcount. It is sustainable cash flow.