Conditionals can get confusing very quickly. Why not avoid them altogether? Here's the idea:

For each of your individual subroutines, you can define a private subroutine that actually does the work, plus a public subroutine that gets the database handle, calls the private subroutine, and then disconnects. For example:

sub make_report1 {

  my $dbh = &_get_dbh;
  &_do_make_report($dbh);
  $dbh->disconnect;
  1;
}

sub _do_make_report {
   my $dbh = shift;

   ## etc...
}

sub make_all_reports {

  # connect to the database
  my $dbh = &_get_dbh;

  &_do_make_summary_report($dbh);
  &_do_make_report1($dbh);
  &_do_make_report1($dbh);

  ...

  # close the database connection
  $dbh->disconnect;

  # return happy and healthy
  return (1);

}
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If you get tired of writing the stub subroutines, you could autogenerate them with autoload. This would add some overhead. Namely, you could define an autoload subroutine like this one:

package your_package;

sub AUTOLOAD {
    no strict qw(refs);

    our $AUTOLOAD;
    $AUTOLOAD =~ m{ (.*) :: (.*?) $ }x;
    my $dispatch_name = "$1::_do_$2";
    if (defined &{$dispatch_name}) {
        *$AUTOLOAD = sub {
            my $dbh = &_get_dbh;
            my $rc = &$dispatch_name(@_);
            $dbh->disconnect();
            return $rc;
        };
        goto &$AUTOLOAD;
    }
    else {
        croak("Unable to autogenerate method for '$AUTOLOAD': no such 
+function '$dispatch_name'");
    }
}
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That way, you could just define your _do_* subroutines, and the public versions would be autogenerated the first time they are called.

On the other hand, Masem's point (and others) are well taken. You can avoid doing all of the above by having your _get_dbh function work like so:

$your_package::DBH = undef;

sub _get_dbh() {
    defined($your_package::DBH) 
        and return $your_package::DBH;
    $your_package::DBH = DBI->connect...
    return $your_package::DBH;
}
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Update: Added autoload section.

Update: Added "on the other hand..."

stephen