Periodically capture cell values

[Digger88]

Hey guys,

I posted this yesterday in the General forum but perhaps the solution is a macro so I thought I might repost it here.

I have a problem I would love a solution to.

I would like to know how to capture a cell value at a specific date each month in a situation where this cell can change value as it is a formula.

For example, the cell returns a percentage that is derived from other data that can change regularly. It may be 45% today, but a user may alter other data in the spreadsheet and it could be 67% tomorrow (or any other percentage).

I want to graph a monthly trend of how this cell value changes by capturing the cells value on the 20th day of every month, or it would also be ok to work on a periodic snapshot of every 30 days.

Any suggestions would be greatly appreciated.