If you feel that 5 years will not be enough for you to accumulate Bitcoin, then you can extend your number of years you wish to accumulate your Bitcoin in as much as you have a steady cash flow that can back you up in your journey, there is no specific time frame for Bitcoin accumulation, that is why it is good you go into long-term investment, like let's say 10 years -20 years or more depending on how long you want it to be so that you will have reasonable amount of Bitcoin in your portfolio in other to have good profit at the end of your investment circle.
There is a length an investment can go and it becomes an overstress investment because the budget has become too long to still hold the longing of an investor towards it because five years of Bitcoin investment has it advantage, ten years also does has it own advantage and twenty years but looking at the motivational aspects the disadvantage of five to ten years is very minor compare to the twenty years because the early we have the budget to hit the more eager for the investors to be there but when is too long the investment will start be coming very uninteresting and there will no be urge for consistency, though not for all but for some people.