Should I use upgrade with purchase or FF only

[JVeteto]

We are planning to go IAH-HNL on CO and wonder if our chances of getting first class tickets are better if we purchase a ticket and use an upgrade with our FF miles or just try to get the entire ticket with FF miles. Thanks.

[Nugget]

I'm not sure how your chances will differ, but ff you buy the ticket and upgrade with miles you'll earn miles for the flight. With an entirely reward ticket, you won't earn miles for the flight.

I only do full reward tickets for companions who don't care about earning miles towards status, I always prefer to pay for the base fare for my own travel so I can work towards platinum with the flight.