I have a budget going wherein debt and income figures are controlled by a master cell, and this allows me to change numbers in one location. e.g. my monthly gas bill is (uh um, was) $200. So I have a cell named "gas" $200. In the gas column is the formula =if(day(b2)=25,gas,""). So if it's the 25th of the month it enters the gas amount $200.

But the cost is changing, and if I change the master gas cell, all cells refereing to it will change, even past dated cells, where the cost is already recognized.

How do I get excel to drop the formula for all cells dated prior to today? In doing so only the amount would be left in the cell, and it would not be linked to any other cell. This way I could manipulate my projected budget without effecting the realized budget.

Thanks in advance.
g.