My suggestion: have the users start with the big hitters (house, income, savings) and then add more and more. Users could see the model change as they go and the onboarding process itself would become informative as they see the effect of their various assets, 401Ks, asset sales plans, etc.
You also really need monte carlo simulation to elevate this far above 'pretty version of my excel spreadsheet' into 'powerful financial planning tool' category.
Lastly, there is one always overlooked part of retirement planning which is that spending plans should not be set-in-stone. For example, if you plug "spend X per year" into a monte-cargo retirement calculator to get a 95% chance of not running out of money you will need to have a lot. But, if you are willing to adopt a spending policy of 'spend X per year unless there is a stock market crash, in which case spend .75X for three years' you will need a lot less. If you are willing to modulate your spending in response to events you can be comfortable with a lot less.
These are excellent suggestions, thanks for the thoughtful feedback. For onboarding, I initially tried a version of what you suggested, but in usability tests many felt there was too much on the screen. Perhaps now it is too minimal though -- I'll think about how to find a better middle ground.
You're spot-on about the need for Monte Carlo simulations. A robust Monte Carlo mode with a variety of variables you can control is the next development priority.
And great point on flexible expense plans. I'll consider how to build some (hopefully) intuitive UI widgets to allow for that in the Monte Carlo mode.
My suggestion: have the users start with the big hitters (house, income, savings) and then add more and more. Users could see the model change as they go and the onboarding process itself would become informative as they see the effect of their various assets, 401Ks, asset sales plans, etc.
You also really need monte carlo simulation to elevate this far above 'pretty version of my excel spreadsheet' into 'powerful financial planning tool' category.
Lastly, there is one always overlooked part of retirement planning which is that spending plans should not be set-in-stone. For example, if you plug "spend X per year" into a monte-cargo retirement calculator to get a 95% chance of not running out of money you will need to have a lot. But, if you are willing to adopt a spending policy of 'spend X per year unless there is a stock market crash, in which case spend .75X for three years' you will need a lot less. If you are willing to modulate your spending in response to events you can be comfortable with a lot less.