General database query.

[John Fitzsimons]

Suppose one has a field that is likely to have no more than 20
characters in. Would there be any practical difference between 
making it a varchar or one with a limit. 

In other words would limiting the field to 200, 100, or 20 be likely
to make much (any ?) difference ? For example, as an estimate, 
would a 100 limit be twice as fast as a 200 limit ? If only 20
characters existed.

Regards, John.