Different flights and tickets give you a different number of miles. If you are serious about accumulating miles you can spend a great deal of time and effort attempting to optimising how many miles you earn.
If you just 'attach a unique identifier to your account' you aren't going to get much out of a frequent flyer programme.
>If you just 'attach a unique identifier to your account' you aren't going to get much out of a frequent flyer programme.
If you're on a consistent route (ex: SF to NYC or London) picking an airline and sticking with it when you fly in every week/month will absolutely rack up points.
If you just 'attach a unique identifier to your account' you aren't going to get much out of a frequent flyer programme.