Isn't the point to change as you get closer to retirement? When your investments have a decade plus to recover, leave them in aggressive investments. There is a risk that a decade+ recession might mean delaying retirement, but in that situation delaying retirement is likely the best option even if your money was in s safe investment.
Once you are close to needing some amount of money, say X a year, then you don't have time for that X to recover, so the idea is to move X into a safer investment so it won't go up or down. Any money you don't need is still in aggressive options that have time to recover. Now you need X money every year, so you decide how many years you want to sacrifice growth for safety. Maybe 5 years, maybe 10 years. Call it Y years. Simulations show the historic optimal Y, though I don't recall the exact number and some people might want to gamble depending upon how much freedom they have to change X if needed. So X*Y is roughly the amount of money that needs to be in safer investments.
This all ends up being too complicated a math equation to optimize for the average person, so percentages are given that are much easier to follow which roughly work as a solution to this equation.
Individuals should be able to come up with their own plans based on what they want. For example, if I'm heading towards an early retirement, I might leave all my money in aggressive investments because if a market downturn hits, I'm okay with working a few more years before retiring. I'm also aiming for a retirement with big X spend a year, but have plans on how to live life if I have to move down to medium X or small X. Others might be aiming for a retirement of X and won't be able to make finances work with les than X, so they have to take a much safer approach to guarantee a retirement that doesn't lead to running out of money.
It really depends upon your age, your financial situation, what you want to do in terms of passing down money--and, as you suggest--if retirement means opening the money funnel on extravagant vacations... If you're comfortable with your ongoing situation with very conservative investments, that's probably what you should do. If you want to play the typical equity numbers over a reasonable timeframe, that may be a better bet. I've certainly been ratcheting down my equity, especially individual stocks, over time even if the expected value is probably lower.
Once you are close to needing some amount of money, say X a year, then you don't have time for that X to recover, so the idea is to move X into a safer investment so it won't go up or down. Any money you don't need is still in aggressive options that have time to recover. Now you need X money every year, so you decide how many years you want to sacrifice growth for safety. Maybe 5 years, maybe 10 years. Call it Y years. Simulations show the historic optimal Y, though I don't recall the exact number and some people might want to gamble depending upon how much freedom they have to change X if needed. So X*Y is roughly the amount of money that needs to be in safer investments.
This all ends up being too complicated a math equation to optimize for the average person, so percentages are given that are much easier to follow which roughly work as a solution to this equation.
Individuals should be able to come up with their own plans based on what they want. For example, if I'm heading towards an early retirement, I might leave all my money in aggressive investments because if a market downturn hits, I'm okay with working a few more years before retiring. I'm also aiming for a retirement with big X spend a year, but have plans on how to live life if I have to move down to medium X or small X. Others might be aiming for a retirement of X and won't be able to make finances work with les than X, so they have to take a much safer approach to guarantee a retirement that doesn't lead to running out of money.