Do you know the story of the donkey in the middle between a bucket of water and a pile of hay? https://sive.rs/donkey https://sive.rs/donkey So the answer is:

Do you know the story of the donkey in the middle between a bucket of water and a pile of hay? https://sive.rs/donkey https://sive.rs/donkey So the answer is: one at a time If you can't decide, say, if all subjects are the same level of interest to you, pick one at random and spend 5 years on it. See where that gets you. If you are satisfied or bored, pick the next subject.