In reply to GridNorth:
If your rope's had a dunking or you've been out on windy days with lots of salt spray in the air then wash it - salt crystals will abrade the fibres. However, you're likely to retire a rope for other reasons before salt crystal abrasion has much effect.
Metalware needs regular rinsing - salt is hygroscopic and will absorb moisture from the air and continue corroding stuff until you rinse it away, especially aluminium.