In order to get effective success from Bitcoin one should emphasize on depositing on a continuous basis and should have multiple or more depositing efforts than in one cycle (as you mentioned 4 years). Your success depends on getting a large holding by increasing your savings scope with discretionary income Here your mental strength and discretion can be taken as the criteria for success.
Mental strength and discernment are enough to propel an investor to success. There is no substitute for being consistent and long-term to succeed in Bitcoin. While we cannot guarantee success, being consistent and long-term can increase our chances of success. Having a proper plan for investing is most important. Of course a person can add his own strategy to the plan, he can add something new or something different to the plan according to his situation. Many times a person adds an emergency fund to his plan, while others adopt a different strategy without having an emergency fund in his plan. But I think it's important that you have enough cash flow.
The most important thing for an investor to start investing or to manage investments is to have an alternative source of income / to have a reliable source of income. If you ignore the fact that your income is not sufficient to manage the investment and you start investing and if you do not find an alternative source of income or a reliable source of income very soon, then you are going to lose your investment. Sometimes your luck can help you. But you can't get into investing by relying on luck. Of course, it's best to get into investing by making yourself investable (getting basic knowledge of Bitcoin or investing, arranging an alternative income/an income source and making up your mind to invest).