@secondcor521 what does your AA look like? Would you mind sharing? You nearly did below, but curious. Also, how have you determined your "maximally safe AA?" I've used FireCalc and cFIREsim, but I haven't found it to matter much whenever I go from 100% index funds, which is where I'm mostly at now, to adding 10% bonds. The success rate only changes by about 1% point. I'm curious if you have any tips, or tools for getting ones AA fine tuned? I'm working to do that now.
My AA is 97/3, as mentioned before - 96.85/3.15 if you go to two decimal places. If you include cash, it's 96.44/3.14/0.42.
My maximally safe AA method is as follows. May not be right, but it's what I do. I'll try to explain each step as to why.
1. I plug all of my actual numbers in to FIREcalc. For the term, I take 90 minus my age. The reason for this is to start with the actual situation I'm in and take a conservative estimate on life expectancy (i.e., I have only about a 20% chance of making it to 90).
2. I then select the 95% spending level success in FIREcalc and replace my spending amount in FIREcalc with whatever that number is. The reason or idea here is to stress my actual situation a little bit and reveal AA differences.
3. I then choose the AA option on the investigate tab. This shows me how success rate varies with AA.
4. I then choose the highest stock AA that is consistent with maximum success rate. (Tie goes to higher stock allocation, basically). I choose higher stock AAs because they typically have higher residual values for the same success rate. This AA is typically 90/10.
5. I then divide my stash into two piles: One which I will spend before I die, and one which I won't. I take my current actual spending and multiply that by 25 and that is the first pile. The rest of my stash is the second pile.
6. The first pile is allocated according to the result in step 4 - 90/10 in this case.
7. The second pile is allocated 100% stocks, because I expect that to go to my kids when I die in 30 years or so.
8. My spreadsheet does the math between first pile and second pile for me and spits out the target AA to bonds. Since my spending is an input in step 5 above, the bond allocation increases slightly as I spend more.
At the moment my target bond AA in step 8 is 3.23%. My actual bond AA at the moment is 3.15%. Given that I'm in the expensive part of the year (Christmas is a big spending period for me), that's close enough.
...
The above is way too complicated, and I'm probably way too analytical about it. Honestly anything within 5 to 10 percentage points is probably about the same. So I would say that it's really not necessary to dial it in any closer than that. So I see differences between 60/40 and 100/0 and 30/70, but I don't see any meaningful difference between 80/20 and 75/25 and 85/15. And even less between 60/40 and 62/38 and that sort of thing.