I would argue that financial planning, be it conscious or unconscious, controlled or uncontrolled, starts around primary or latest secondary school, when your future academic and career paths already start to be defined and will potentially be compounded over decades. In any case, it is important to ask yourself certain questions about your desired (and realistic) standard of living, career, family plans, etc. and ideally formalise a financial plan that you can use for future guidance.
Are you an individual or institutional investor paying deposit fees, trading commissions, fund management fees, fund performance fees, transaction and income taxes?
While it is not always true that lower costs = better performance, since in some cases lower costs may mean lower quality, it is often the case that there is room for cost optimisations in a portfolio. A coaching approach (questions/challenge instead of advice) to cost analysis and optimisation helps you to focus on the trade-off between cost and (potential) benefits, and between high-cost solutions in a niche and low-cost solution in another niche or even broader market, while leaving the investment decision completely within your control.