Unless the database is huge or performance isn't a concern you should probably just use a char field. The real payoff of varchar is wildly variable data where most of the time the varchar field would be small. In these days of huge hard-drives you might as well fix the field at the largest size and get the performance win of the DB knowing how many records per page you will have. If neither performance nor size matter, do what-ever makes you happy! =)

varchar for size, char for speed

P.S. The same boss that insists on int's will one day ask you how you can get (1-555-use-perl) in that DB...

--
$you = new YOU;
honk() if $you->love(perl)