[Sorry if this is a repeat question, I did a search but didn't find anything.]

When does a voucher need to be used by? I assume the base expiration date is 1 year from date of issue, but is that when:

- travel needs to be started by?
- travel needs to be completed by?
- ticket needs to be purchased by (which actually gives you 1yr + ~11 months).

Also, is it correct that you can only use 1 travel voucher per purchase? Is so, I assume this is certainly true for online purchase (maybe only one field for voucher information), what about if you ticket in person?

Thanks.

Jeff