Configure custom fields to be required based on the value of another custom field

Need to make specific custom fields required when creating or on a transition screen based on the value of another custom field.

For example, custom field Existing Client, Y/N
If Yes, Current Products, Pricing, and # of Licensed Users are required
If No, Interested Products and Proposed User Range are required

Currently, it causes issues to go back and forth between individuals because the reporter or prior assignee doesn't know that certain fields are required.
Having this would improve cycle time, reduce frustration, and make the workflow appear smoother to our users.