said by JMJimmy:No, they're pre-paid cards. As stated above, they're used for multiple services (local vs long distance calling, texting, data, etc)
The cards have none of that. They are used to add to the balance of a pre-paid cell phone plan. You can wait months after purchasing the card before applying it to your or another person's prepaid cell phone account without it losing any value.
That it's common practice to expire pre-paid cell phone balances after a number of days is really a separate issue and happens if you use top-up cards, a credit card or a debit card to add to the account balance.