If you're asking that question, you are probably using far fewer subroutines than you should. :-)

Some suggestions:

• Try to put everything in your code that does something you can name as a distinct action in its own sub. Subroutines should ideally not be bigger than a paragraph of text. In other words, a single sub should be easy to read and do something that's easily described.

  Don't do:

  sub get_me_a_drink($drink_name) {
    if ($drink_name eq 'soda' or $drink_name eq 'beer') {
       # go to fridge
       # open fridge door
       # get drink
       return $drink
    }
    elsif ($drink_name eq 'coffee' or $drink_name eq 'tea') {
       # get water
       # boil water
       # mix ingredients
       return $drink
    }
    die "Can't make this drink";
  }
  [download]

  Do this:

  sub get_me_a_drink($name) {
    if (is_cold($name)) {
       return get_from_fridge($name);
    }
    if (is_hot($name)) {
       return brew_hot_drink($name);
    }
    die "Can't make luke-warm drinks";
  }
  [download]

• Use less variables and more function calls (don't count the variables that hold your subroutine arguments). This will make your code look less like a list of steps and more like a sentence. In other words, don't do:

  sub brew_hot_drink {
    my $ingredients = shift;
    my $water = get_water();
    my $hot = boil($water);
    my $drink = mix($hot,$ingredients);
    return $drink;
  }
  [download]

  but do

  sub brew_hot_drink {
    my $ingredients = shift;
    return mix( $ingredients, boil(get_water()));
  }
  [download]

• When you're feeling comfortable with this, take a look at the things you can do with anonymous subroutines (i.e. the flexibility you can get when you can pass bits of code around instead of just bits of data). This is a large topic, and more advanced, but you should learn at least the basics as soon as you're getting comfortable. merlyn's done a column on this topic. Also, see Why Closures?.