Later today, I am required to cross a large ocean, commanding a large aircraft, with 3 other pilots with whom I have never flown before. I am very relaxed in anticipating this flight, because I know that the 3 crew members will be operating the aircraft in exactly the same manner as I do, and in the same manner as all of the other pilots with whom I've flown in this company. My state of relaxation arises from the knowledge that we all operate to the same SOPs.
SOPs considerably enhance safety by removing a large potential for human error arising from poor crew communications, it's not necessary to communicate my intentions if my intended actions are STANDARD, the other crew member(s) will expect me to follow standard procedures unless exceptional circumstances dictate otherwise.
A particular SOP may not be perfect, but it is a proven procedure. There are many ways to skin a cat, any of several ways may be feasible, but if the SOP specified by the operator is safe, proven, and universally complied with by all crews, uncertainty is removed from the cockpit with numerous safety benefits. There are also legal 'benefits' to the crew if, in an investigation following an incident or accident, they have been found to be following SOPs.
SOPs are established for all ANTICIPATED Normal, Non-Normal, and Emergency Procedures, but it must never be forgotten that the S in SOPs stands for Standard, there may be extenuating or unforecast non-standard circumstances where the best judgement of the Commander and His/Her crew is required. In fact, the first SOP on the list should be "Nothing in the following replaces good judgement in the field under extenuating circumstances."
Regards,
Old Smokey