Now, that being said, every diver has to know and understand their personal limits and experience. No diver should ever allow him- or herself to be coerced into going on a dive. Not through peer pressure or disparagement of courage or any other means. It is always ok to skip a dive or even “call” (end) a dive you’re already on if you are really uncomfortable with the situation.
When we are novice divers we are advised to dive within the limits of our training. In Southern California where I live and teach, students learn to dive in relatively cold water 55-65° F (12-18°C) wearing 7 millimeter wet suits, hoods and gloves and often experience surf and surge and limited visibility. We often say that if you learn to dive in California, you can dive almost anywhere. But even with that sort of basic training there are going to be times when current or surge or limited visibility or the depth of a planned dive is far enough beyond your experience that it concerns you. When this happens it is perfectly alright to say so and not to go on a dive. So how do you move on? It is sometimes appropriate to dive incrementally beyond your experience so as to gain that experience. For example, if you have never dived beyond the 60ft/18m depth from your open water check out dives and the opportunity presents itself to dive to 80ft/25m in excellent conditions i.e. good visibility, little to no current, temperatures within your experience, an experienced buddy (or with a divemaster or instructor ideally) that could be an appropriate time to gain more experience.
I personally make it a point to never dive with a new piece of equipment when I’m with students. My attention must always be with my students and I never want to be distracted by being unfamiliar with something new. I will try new gear on my own fun dives. What does this mean for a new diver? Just this, if you are trying out some new equipment my strong suggestion is to do so on an easy dive with pool like conditions or actually in a swimming pool. Every diver should be very familiar with his/her equipment. I say to every class, “Diving is easy, we don’t really train for the diving, we train for the rare times when something goes wrong.” Know your gear.
Obviously every diver is different: experience, fitness, proficiency, currency (when and how often they have dived) not to mention state of mind/body; did he or she have a stressful work week, just get over a cold, have difficulties sleeping because of travel or excitement and so on.
Everything is a matter of judgment, judging yourself and judging the conditions and circumstances. I’ve been diving for 40 years and I’ve never had a serious problem while diving. I attribute that to diving conservatively, diving within my limits, extending those limits incrementally and continuing my diving education throughout. I highly recommend this approach. Be safe and happy diving.
“Scuba diving is a recreational sport. You don’t ‘have’ to do it. You choose to do it.”