[AccessD] Autonumber Assigned Immediately

My point would be -- if there are no rules, why bother until there are some?
It might never happen. 

Susan H. 

Six months later you are told that all the numbers have to be padded to 6
digits. Ok, either change the field to a text field (if it wasn't such
already), revise the number generator accordingly, and run an update query
on the existing records to include the padding, or find all uses of the
'number' field everywhere in the database and change the formatting of the
number display. [I know which choice I would make :) 

Then a year down the line the suits say "You have to include an alpha prefix
that shows which office created the record". Fine (As long as you can
identify the office within the rest of the data). You change the 'number'
generating code to tack on the prefix for new records and then run an update
query to add the prefix to all the existing records. 

Sit back and wait for the next bright idea about what extra information can
be stuffed into a 'serial number'. All of this is just a minor pain in the
butt because of course you are not using this field as a Primary Key, that's
handled by an autonumber that no one sees, so all your relationships are
intact.