Just used a ~4 year old refill card and got more than I expected!

[jine4]

Data point for those doubting that refills don't expire for a long time: I bought the $25 card 11/2008, used it now and it worked!
Also got ~218 minutes or a little more.
It actually brought my nominal minute rate down from ~12.79 cents to ~12.52.
I have Gold rewards on PAYGO.

[luther349]

They don't expire until the used

[moto94536]

yea. I also have tmobile prepaid for backup, since 2005.. I either fill with $15 or $50, depending on how much balance I have left on the account..

I am a gold member too. It is more cheaper when I refill with $50, and I get 15% more. so it came down to about .11 cents a minute.