I would like to setup my spreadsheet so that a user
cannot change the data after 1 week. What would be
a good way to block users from changing their own
data after 1 week or longer???

I figure, I can processed Workbook_Open() and test
how old the workbook is. From this point, is it simply
good enough to password protect the sheet???

I am not completely confident that the "Sheet Protect"
mechanism is completely secure, I mean, can't a skillful
user open up the VBA editor and write code to change
data on the protected sheet???