Lets see if this will help:
We are just 2 and older (mid to late 60's). We live in a state with income taxes (about $1K a year). We are both on Medicare (remember it cost for that now ($2,244 a year for to people and rumored to go up about 17% in 2008). Our RE taxes run about $7.5K a year on this condo.
So these fixed costs we cannot do anything about (unless we sell, move, etc.,)
SS Medicare: $2,240 (I guess this could equate to a pre-65 yo medical insurance cost)
RE Taxes: 7,500
Other Fixed: 3,525 (Car Insurance (one car) $600, Condo Insurance $165, Condo Fee $230 a month ($2,760 a year); includes Water, Sewer, Trash, Outside Maintenance, Snow and Lawn Service and Insurance).
So total fixed are about $13,265 to which the variables like utilities (Electric, Gas, TV, Phone, Internet), then Gifts, Car Maintenance (which I do myself, for the most part) and usually have driven cars under warranty (spend too much on cars), Gasoline for local and trips, Other travel expenses, Food (we do not eat out very much) and other unforeseen large expenses. I have pretty good data on what we spent over the past 10 years or so, but your figures will vary. We spend about $27,000 a year, in todays dollars, to live. Our RE Taxes are high, we live in a Income taxed state, live in a pretty winter-cold state (Central Ohio) so you may have to adjust to those numbers. As an example we lived about 20 years in Florida (1986-2005) and spent about $22,000 a year down there in 2004 dollars.
Edit the above costs INCLUDE Federal Income Taxes (just to clarify).
PS: We have 0 debt, Condo paid for, 05 car paid for, credit cards ALWAYS paid off monthly and are in reasonably good health (for a couple "older than dirt").
Hope this gives you enough detail to help you.
OAG