It's very nice to have a number say in the about box that the customer can read you, and you can immediately find the version.
Write a program which outputs the current date to a text file called something like 'today.inc' and include it with {$include today.inc} in each of your units.
Then integrate this little tool into your Delphi IDE and run it every time you make a new build.
// by Martin Larsson, martin.larsson@delfi-data.msmail.telemax.no
// include file "today.inc"
const
_day : string[10] = 'Monday';
_date : word = 12;
_month : word = 8;
_year : word = 1996;