That all depands on the experience that you have of organizing, and planning. There are alot of things the can go very wrong and cost quite a bit if everything and everyone are not in sync. The size of the job would be the other factor that would have to be considered. Small deck job with outside lighting shouldn’t be a problem, but a major project would be quite dirrerent. When in doubt hir a GC
Organizing subcontractors who specialize in each area of construction and remodeling takes alot of coordinating and experience with their work. If you are unfamiliar with the subcontractors and they are not used to working with the others you can run into delays, miscommunication, etc. You may or may not save money in the long run, but hiring a general contractor or Certified Kitchen & Bath Designer will save you time & aggrevation. They have subcontractors they have experience working with, people they trust and can depend on. This can be economical in the long run.
If you hire a contractor that is qualified to complete all the different task it is more economical compared to hire few different individuals or contractors.
Dpends on your type of project and your level of comfort in deeling with workers and contractors. Small handy man projects can be done by single person and helper. Larger projects require permits and licensed sub contractors to perform the work. More complicated projects, best hire a GC. Try not to have too many cooks involved.