The best rule of thumb is to have 100 minus your age in equities. (Percent)
One thing I was going to add to the discussion is the individual’s personal situation.
For example, a retired couple that are both knocking down fat government pensions with gold-plated medical retirement plans might be able to take a little more risk with their portfolio, as they really don’t “need” their nest egg money to meet basic living expenses. That is assuming that their house is paid for, they don’t have kids in college, etc. In other words, their money is “play” money for wants instead of needs.
Conversely, people who must rely on their portfolio to generate cash for everyday living expenses must be a little more careful to not crack the egg and see the yolk run out on the floor.
But an exercise in market timing, and trying to pick the absolute top and bottom, and then deploying ALL your assets to match is mighty risky, at least to me.
All of the above assumes you’ve mastered Rule Number One.
Spend less than you have coming in.
If that rule isn’t observed, no amount of planning, market timing, stock tips, or anything else will work.
Ever.