I've been asked to write a macro to protect a worksheet from being
accidentally changed. There are about 10 users who each enter data on
their own specific worksheet, and each of them has the password for
their sheet only. (There are additional sheets and macros that tally
the information entered and graph it and so forth.)

What my customer wants is that if they try to make an entry, the
password box automatically appears (preferably in place of the box
warning that the worksheet is protected) so they can just type their
password in, make the changes they want, and when the close the
workbook or go to look at any other sheet, the worksheet they edited is
automatically password protected again. If they accidentally click in
someone else's worksheet, they will get the password box and just hit
Cancel and go to the correct page.

I read Walkenbach and did some research here, but I'm still not sure
how to approach this, even though I think once I figure it out, it'll
be fairly simple. Right now, I'm confused about the "Change" event.
Walkenback warns that it's not triggered by some kinds of actions that
you might expect it to be triggered by. I found there is both an
application level "Change" and a "SheetChange", but I'm not sure which
one would be best here. Any suggestions, both as to which is best and
any other ideas/warnings as to my approach?

This is not a security issue, just protection from an accidental entry
messing someting up.

Thanks in advance.