Microsoft Points cards and codes that you have purchased and choose to redeem after your account has transitioned will expire one year from the date the Microsoft Points are redeemed.
Ok here is the clarification:
http://support.xbox.com/en-us/billing/microsoft-points/microsoft-points-retire-faq
So your cash doesnt expire, but if your account has already transitioned to currency, any points cards added to your account will expire. That makes more sense and seems fair as exchange rates change. So it would be possible to buy a $5 points card, that could be worth $6 in a year.
The currency we add to your account at the time of the transition will expire on June 1, 2015. However, the currency you purchase and add to your account after the transition will not expire.
It is, to put it mildly.well I had points on my account then they moved those to cash currency so MS wording is confusing as s*** to me.