Here's yet another way to do it, using DateTime::Set for recurring events. It's also possible to modify the "recurrence" callback to shift the exact day if, for example, paydays can't be on a weekend, and there are even modules that calculate holidays for different regions.

use warnings;
use strict;
use DateTime;
use DateTime::Set;

my $paydays = DateTime::Set->from_recurrence(
    start  => DateTime->now,
    before => DateTime->new( year=>2019, month=>7, day=>1 ),
    recurrence => sub {
        my $dt = shift;
        return $dt->day < 15
            ? $dt->truncate(to=>'month')->add(days=>14 )
            : $dt->truncate(to=>'month')->add(months=>1)
    },
);

print "paydays: ",$paydays->count,"\n";
# - or -
my $iter = $paydays->iterator;
while ( my $dt = $iter->next ) {
    print $dt->ymd, "\n";
}

__END__

paydays: 41
2017-10-15
2017-11-01
2017-11-15
...
2019-05-15
2019-06-01
2019-06-15
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