There are hundreds of financial planners on line where you put in your estimates of assets, and return and inflation, and come up with the amount you need to retire. In our case it doesn't work... All of the planners make the assumption that you will want to maintain your asset capital until you die... In our case, had we followed their plan, we NEVER would have retired.
We just decided to die at age 85... dead broke. Made our planning much easier. Personal decision of course, but if you plan to spend down capital assets, it makes planning easier.
Our plan is extremely simple... On the spending side, we have three different budgets that we can adjust as circumstances warrant. Best case... Nominal... and Austerity.
On the Asset/Nest Egg side, We boil our assets down into three categories.
1. Fixed assets... house, auto, and other valuable non cash items... real property, jewelry, . We do not count household goods... (experience tells us that this is not realistic)
2. Non Income producing assets... bank accounts, cash, cash value life insurance policies.
3. Income producing assets... stocks, bonds, annuity.
All of these items are kept on a spread sheet and periodically updated. It's easy to come up with a total value... and then to average the income from the total...
To calculate where we stand in our retirement plan, we add
a. Social security amount.
b. Amount of interest earned on income producing assets.
c. ... and add the Total Assets divided by the number of years between now and age 85.
That establishes how much we can spend, which we then adjust to our best/nominal/austerity budget.
Sounds funky, but it works,and it takes about 2 minutes to tell if we're on budget or not.
The second part of this budgeting thing, is that we've been blessed by not having any debt. All of this makes for very simple accounting.