My mom will be getting me a Security Bank Wave Mastercard supplementary card!

As the title states.

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I'm a graduating student and will be buying my own groceries, skincare, hygiene, etc. once I have a job and will be using the supplementary card. I also have my own Maribank debit card.

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Any tips or advice? When would it be better to use my Maribank debit card rather than the supplementary card?

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Will plan on having my own Security Bank Wave mastercard in the future. Or any NAFFL with good rewards/cashback.