Same kind of confusion with Maxroam Classic +32:
Does my credit expire?
180 days after your last chargeable call or SMS message your credit will go into an inactive state. You must top up to remove your credit from this state within 180 days of it becoming inactive. As soon as you top up your credit will be reactivated and added to the amount that you topped up by. If you do not top up within 360 days from your most recent activity, your remaining balance will be lost.
Will my credit expire?
No, never.
Will my SIM and account expire?
No, never.
From:
http://www.maxroam.com/Info/Faq.aspx