Consider Bitcoin investment as a type of savings, which can be called Bitcoin savings. Set a goal and keep chasing that goal consistently. How long your savings journey will be depends on your goal, but at least keep saving for a cycle (4 years). There is no specific time limit on how long you can extend it, in this case you have to prioritize your goal. It is your sole decision whether to extend your savings journey or stop after achieving the goal. One thing that is advisable is that never sell the entire investment.
If you are investing in Bitcoin and consider it as an investment, there is a high probability of tampering with the investment when you are really in need of money. This is the reason why it is important for investors to have a backup fund while investing in Bitcoin.
This backup fund is the money that can be used for emergencies when money is needed. Investing in Bitcoin and considering it as a savings investment makes it impossible to keep your eyes and mind off it when you really need money to solve problems. While investing in Bitcoin, you also need to plan for having backup funds that can save you when you are in trouble. If you don't have them, you might be depending on your Bitcoin savings investment to save you when you fall into an emergency.
We need to have an emergency fund to protect our investments. If there is no emergency fund, then in that case, we need to create an emergency fund along with the investment. After creating an emergency fund, you can create separate funds. For example, you can create a backup fund, a reserve fund, etc. so that your investment can be more secure.
But it is not always right to take money from the emergency fund. When you have no other option except your emergency fund, then you can take money from the emergency fund to deal with your financial crises. You can create a backup fund, etc. to deal with small financial crises.