I use mileage for spontaneous (non-budgeted) travel, such as (USAir redeemed on SwissAir) going to Turkey for a friend's wedding which he did not spring on me until 1 month in advance. Unplanned, unbudgeted, and a great experience which would not have been possible without the miles.
(This post elevates me from Junior Member to Member!)
[This message has been edited by chalf (edited 04-26-99).]