What can virtually eliminate equipment-related stress for divers?

Selecting equipment that fits well and is used properly is fundamental in mitigating stress for divers. When a diver is comfortable and confident in their gear, they are less likely to encounter issues that could complicate their dive. Equipment that fits properly minimizes the risk of discomfort or injury, which can significantly contribute to a diver's mental state. Additionally, correct usage of equipment ensures that the diver knows how to operate it effectively, reducing anxiety about potential malfunctions or mishandling while underwater.

The other options may address specific aspects of dive readiness, but they do not provide the same level of overall stress reduction. For instance, while using rented equipment might offer a solution in terms of availability, it does not guarantee a good fit or familiarity, which are crucial for a smooth diving experience. Adjusting rental gear before the dive can help but does not ensure the gear will meet the individual's specific needs during the entire dive. Keeping extra gear handy could offer a safety net, but it does not directly impact the comfort and operational familiarity with the primary equipment being used.