The entitlement and the arrangement are two things
The law establishes that a weekly rest day exists; the household and helper decide the workable specifics. Writing down the chosen day and how an occasional worked rest day is handled prevents the most common disagreement — a rest day quietly absorbed into ordinary duties.
A rest day is time off, not a lighter workday. Agreeing this in advance, in the contract, protects both sides and makes the arrangement reviewable rather than remembered differently later.
Region changes the baseline
The Employment Act reaches Peninsular Malaysia and Labuan, so its rest-day provision applies there. Sabah and Sarawak have their own labour ordinances, so a household in those states should confirm the rest-day position with the state rules rather than carrying over the Peninsular baseline.
The rules-cluster guide on rest days sets out the detail; this read is about treating the entitlement and the written arrangement as separate steps, both of which matter.