I just computed it.
For reference, here are the success rates for 50 year periods at 4% WR as a function of (constant) stock allocation:
50%: 79.8%
60%: 86.2%
70%: 90.4%
80%: 92.6%
90%: 95.7%
100%: 94.7%
Now, starting at 50% allocation and increasing to 100% at a given pace, I get:
over 5 years: 95.7%
over 10 years: 96.8%
over 20 years: 94.7%
so 50% -> 100% over 10 years seems to be the sweet spot. I doubt the difference is statistically significant given the small data set though, because stopping at 90% allocation instead of 100% goes back to 95.7%.
Those are very interesting numbers. Even though I have been reading MMM for about 2 years and have seen the simulations that a higher percentage of stock results in a longer success rate, I have 30 years behind me of "when you get close to retirement shift your assets over to 50/50 or 60/40."
I'm 62 and it's get serious about asset allocation time. Logically I should have zero concerns about my stache, and should just leave it in the market to grow for the two kids, because we have about 34 x spending. I'll get $20k in SS in three years and another $18K in 7 years for the wife. We can easily live on $50k so that leaves a $12k shortfall. With about $64k coming with the 4% rule.
All this argument does is convince me logically I can just leave it in the stock market.
But then, "when you get close to retirement shift your assets over to 50/50 or 60/40."
and, "when you have Critical Mass you need to adjust so you never lose it"
is cackling in my ear.
I know that if a 2000 or 2008 happens again, I'll could easily see $400k or $500k disappear in a year.
Yes I will be fine, but still that would stink.
I got through a $240k loss in 2008 and blossomed from 2010 until now.
So that down time may only be 3 to 5 tears, I mean years.
Just some things running loose in my mind.
Edit to add, I had not read the oatmeal believe comic before I posted my two lines of thought, one long ingrained and one new information, that I'm trying to incorporate. While not all that deep it runs in the same
company.
btw, RE: the believe comic, I thought, were they dead or alive, did they cut the roots off and what kind of glue did they have to hold them together. Probably shows a lack of empathy, or a more engineer/science background.