I am a believer in not outsourcing or even delegating customer service. I think it's one task that doesn't scale that all startup founders must do from the very beginning and until the business is no longer a startup, but rather a company in execution mode for repeatable, scalable, business model.
That said, answering customer service emails is time consuming and so the most common answers should have templates that are only modified slightly, as needed. Also, it's worth looking into adding commonly requested information to the site (in the right place) that helps customers serve themselves instead of reaching out for assistance. That's kind of the point of not delegating customer service - it forces you to think of ways to optimize the site and process to save your own time, while getting the valuable feedback you need.
Another one is managing freelancers/contractors. Team of 4-6 could take all of your time if they seek constant direction and guidance. If you are not a subject matter expert for some, it might be hard to come up with goals/tasks and evaluate work on ongoing basis. My solution has been to filter out candidates based on them being proactive on the trial project - I leave room for their input and see how comfortable they are with it (good ones will propose options and are not afraid of giving their opinion). I have been very happy with this approach and the outcome over the last few years (very little time spent managing).
I would say it should be all tasks that you can break down into an exact process.
If someone can follow a process you wrote down and bang 'em out 1, 2, 3, 4... then you can hand those tasks off and focus your time on things you can't create a process out of.