A:Answer You are asking the wrong question......Just because you put a $25 or $35 prepaid card into your account, doesn't mean your service is extended by 30 days.
The $25 card adds $25 to your prepaid account, and the $35 card adds $35 to your prepaid account. How much is taken OUT of your account depends upon what prepaid plan you signed up for. Personally, I signed up for a $30 plan. So every month they take $30 out of my account. I also have it set up that if I don't have enough in the account, they then auto-bill my credit card (this may result in a $5 discount for some accounts).
So if I put in a $25 card, then they will auto-pay an additional $5 when my $30 monthly plan is due. If I put in a $35 card, they will take out $30 when my monthly plan is due, and I will have $5 left over to apply towards the next month.
The balance in your prepaid account expires 90 days after being either of these cards is applied to your account. But this time can be extended by adding another another card to your account. It should be noted that the $10 (and I think $15 cards) expire after only 30 days.