Find the regulamento
Look for the points or cashback terms on the issuer's site or app. Your issuer must give you a way to consult the rules of any rewards program linked to the card (Resolução BCB nº 96).
Check how spending is converted
See whether points are counted per real or per US dollar, and which exchange rate and date the issuer uses for the conversion.
Read the exclusions
Check which transactions don't earn: bill and boleto payments, cash withdrawals, taxes, interest, fees and refinancing all appear as exclusions in published terms such as BTG Pactual's.
Check what happens after you earn
Note where points or cashback go, whether redemptions are capped, and whether expiry follows a partner program's rules.
Work out value per point
Divide the cash price of the reward you want by the points it costs, and compare the result with a cashback alternative and with the card's annual fee.