Expiry has a starting point
Read whether validity starts at issue, purchase, activation or another event. A card bought today may already have a fixed expiry. Do not assume all brands offer the same period.
Partial use is product-specific
Some products retain unused value; others are designed for a single redemption. Check what happens when the bill is below the card amount before spending it.
Check balance safely
Use the balance-check route shown by the issuer or official brand. Avoid third-party sites asking for your complete code and PIN. Keep the receipt and any redemption confirmation.
If a card expires
Contact the issuer using official contact details and ask what options apply to that exact product. Do not assume revalidation or a refund is automatically available.