Here are some of things that I do consider when I cancel a trip, either at the dock or the night before. When winds will exceed 20-25 knots from either direction on the compass rose over a sustained period of over 6 hours. Sometimes when the winds are from the west we can get some inshore wreck dives in. Seas have been building for several days prior and reach 3-5 feet with a time period between wave height of less than 7 seconds. This means they are very steep, close together and high, making getting into the boat very difficult and dangerous.
Ocean currents make surface swims very difficult.
Large and very deep swells have seriously diminished bottom visibility, in conjunction with rough seas usually. The boat has a non-immediately fixable mechanical problem. Diver ability and training is inconsistent with weather and wreck choice. It may not be your first wreck choice, but I cannot or will not guarantee any specific wreck location. I will always cancel at the dock, unless I know in advance it isn't worth trying and I will call to save you or the charter contact to abort the drive.