I have lots of spreadsheets and spend a lot of time futzing with them, in an attempt to try to predict my financial state in 5 - 8 - 15 years and when I will be able to retire. I also know about FireCalc and have played with that quite a bit.
I am wondering, when you use your crystal ball, what assumptions do you make about the growth of your accounts? For instance, say I have $30,000 in a Roth IRA in the VTSAX fund, and I'd like to predict what the balance will be (assuming I leave it alone) in 5 years, or 15 years, should I use 4%, 5%, 8%? What do you do? Say I have $200,000 in TIAA retirement funds. Same questions--how do you anticipate the growth in the next 10 - 20 years?
I realize that no one knows what the markets will do, etc., but I'm just wondering what kinds of assumptions you make as you play with your spreadsheets and try to plan.
Thanks!