To the original "Reasonable Pessimistic Assumptions"...
I think it's unReasonable to Assume that the Pessimistic predictions will all stack up. That's the advantage of using a Monte Carlo type simulation. Over the long haul if inflation is higher then investment returns will probably be higher. If you assume a big market crash then short term inflation will probably be low for a while then investment returns will probably be high for a while.
I'm a poorly educated amateur... Highly educated professionals don't have great track records in predictions so mine are unlikely to be correct either.
I have four versions of my planning spreadsheet including:
- Fairly pessimistic (30% market drop right after retirement, then 4% inflation and 4.5% market growth, SS all taxable);
- Conservatively realistic (20% drop, then 3.5% inflation and 5% growth, SS all taxable);
- Cautiously optimistic (15% drop, then 3% inflation and 5.5% growth, SS still 85% taxable);
- Moderately optimistic (10% drop, then 2.75% inflation and 5.75% growth, SS still 85% taxable).
I'm trying to come up with a spending plan that works for the more pessimistic outlook with "rules" to determine how much extra to spend if we end up with the more optimistic situation.