Well, I found some answers relating to your question. I'm quoting one of the answers, but there are lots of pages via google search, which answer your question.
Quote from ExcelForum.com
under share workbook editing tab check the allow changes by more than
on user ..... box warning this may not work as you require!
sharing like this causes all sorts of problems
if more than one user changes same cell on save they will be prompted
"whose changes to keep" now if they choose theirs the other gets
if they chose other they will have to reenter date elsewhere also
sharing is prone to cause workbook bloat a smallish 1meg file can
swell to 15 meg + quite easily.
the work book often can lose data for mysterious reasons and
formatting changed seemingly on a whim.
users forget to close workbook and when you look at who has this file
open you could end up with 20 or so names many of them duplicated.
so dont share unless you are in strict control of it.
unshare it everynight 9this clears out odd users)
save a copy at least once a day.
it really works best if only one user is likely to edit a field at
say a job list where user one is dealing with job one so no one else
is likely to update that field because they would be on say job 3.
if you can avoid it do so
you have been warned