Does the second crash earn its space?
Use the set list to decide whether another cymbal will be useful.
Look through the set list and identify what you would use a second crash for. It might provide a different pitch, a softer accent, or an easier reach after a fill. If you cannot identify a use this week, try rehearsing with one crash.
Play the passages where you usually alternate between cymbals. Listen to whether the single-cymbal version still supports the arrangement and notice any awkward reach. Keep the second crash if it solves a musical or practical problem.
Removing a cymbal can be a useful practice experiment when you want to reconsider habitual accents. Save the setup that works for the set, then revisit it when the songs change. If the second crash provides a sound or a comfortable playing position you need, include it and mark where you will use it.