I am 51 and my IRAs and taxable account are at 93% equities with a lazy intent to get up to 97% equities or so.
My Dad is 83 and he is at 73% equities.
I forgot to explain why. NW-Bound's comments about what the market might do in the near future leads me to comment on my reasoning.
I do not invest based on expectations about the near term future of the market.
I first start with my age and from that and my general level of health try to determine my remaining life expectancy. Currently I assess this to be about 40 years.
I then look at the maximum amount I can spend with 95% historical success given my portfolio size. I then use that spending level and my portfolio value and use the Investigate option to look at the relative success rate across various stock/bond AAs. I pick the highest level of stocks that is consistent with the maximum historical success rate across stock/bond allocations. Typically this is 90% stocks.
I then take that percentage WR and my current spending and that 90% stock AA and reverse calculate how much of my stash is actually going to be spent on me. The excess will be inherited by my kids. Since they will be inheriting that portion several decades from now, hopefully, I keep that excess at 100% stocks.
Since my WR is currently 0.85%, the math works out that I'll only spend a small portion of my FIRE stash (invested at 90% stocks) and the larger portion will be inherited (invested at 100% stocks). The weighted average is about 98%.
I'm lazy about it because (a) there really shouldn't be much difference between 93% stocks and 98% stocks, (b) it'll give me something to do and feel good about over the next several pullbacks (I rebalanced on 12/24/18), and (c) if I spend more, and I'm intending to try to spend more, then that increases the amount of my portfolio that is needed for me, and thus lowers the target overall stock AA.
If I can make it any more complicated and provide any more explanations that nobody probably cares about, I'll be sure to let everyone know.