Your plans don’t have to be the backup to everyone else’s.

Being easy to reschedule turns into being the one who always gets rescheduled. If your plans move whenever someone else’s firm up, they stop being plans and become availability, and everybody around you adjusts to that without noticing. Flexibility is good, and being the default give is not the same thing. What you intend to do has the same standing as what they intend to do.

The next time something you arranged gets bumped for a better offer, keep yours. Go to the thing. One kept plan tells people more about your time than any conversation about it.