Measure thrice, cut once.
If you measure down the middle of the quilt, cut your strips, pin them on, matching the centers and quarter marks (and any others too) you will be much happier when it comes time to quilt.
If you sew on, then trim, you will end up with what we call "friendly" borders, they "wave" at you.
This quilt had 4 extra inches on one side, 5 on the other. I had to take several tucks.