The answer is 42 ;>

Depends on the 'value' of the data.  From "Mission Critical" to no
importance.

Ed Warren

Well, that depends on how you're using the database. How important is
it that your data is correct? Is it acceptable to have garbage in your
database? If so, then you don't need data validation.

If reports from your database are going into the corporate Annual
Report, or into a New Drug Application to the FDA... you may want to
be sure that the data is in fact valid. If you're keeping a database
of sports scores for fantasy football, it may not be as critical!

There are many ways to implement validation. The simplest to implement
(but most limited and least friendly) is to put field or table level
validation in the Table design. More sophisticated is to use a Form to
do all data entry, and put customized VBA code into the Form's
BeforeUpdate event to check that the data is correct, and warn the
user and cancel the update if it is not. The details will of course
vary with your application.

                 John W. Vinson[MVP]