If you have a fixed-minute subscription (60, 120 or 400 minutes), your calling allowance is reset each month. If you have unused minutes, they are not carried over from month to month.
                    However, if you buy an unlimited subscription* you don’t need to worry about 
                      reaching your monthly allowance. We have unlimited subscriptions 
                      for calls to landlines in more 
                      than 40 destinations (and for some destinations, calls 
                      to mobiles are included too).
                    And if you buy some Skype 
                      Credit, you can use it to pay for calls to other countries 
                      and mobile phones that are not covered by your subscription.
                    *A fair usage policy applies.