Originally Posted by RandD

I want to use 1 RPU that I have left on my upcoming flight to GUM; SAN-LAX-HNL-GUM and GUM-NRT-DEN-SAN. The flights are in July.

My initial thought is to use it for SAN-LAX, LAX-HNL, but these segments have more than 9 seats available for upgrade. On the other hand, GUM-NRT, DEN-SAN are quite full (waitlist only and 2 available).

Should I use RPU on the return flight to lock in DEN-SAN upgrade and hope for CPU for LAX-HNL?