How can I determine the amounts of shifts/hours of work for being a therapist/any person to help with mental health or a marine biologist/ underwater photographer and how can it overtake someone's life (will it take a lot of time out of their day?)
I am sorry I cannot answer the marine photographer question as that is my expertise.
As with anything worth doing, continue to research your interests and perhaps volunteer in several settings to help make your decision.
Balance can be achieved and you can have a fulfilling career and happy family life! Do what you are passionate about and you will never go wrong.
Mental health therapists are often self-employed and get to set their own schedules. The amount of hours worked is determined by how much money that person wants/needs to make. Other therapists work in hospital or institutional settings and have 35-40 hour/wk jobs. The marine biologist/underwater photographer work is a different topic. Marine biologists do original research, whereas photographers are focused on documenting what is there.
Serah recommends the following next steps: