This kit is made to be a no brainer.  You buy 4 of the same pad so that you can swap pads after 1/4 of the car, and the matching polish and you get for free a 500ml bottle of Fireball towel and pad cleaner and a Rockcar pro pad cleaning brush so you can really scrub and clean the pads, plus a free Pegasus microfiber cloth so when you wipe down you know you won't scratch.  Thats over $85 of products for free. 

Why, because when you buy just one pad and hammer it and don't clean it you won't get a good result.  But when you buy 4 pads and swap pads after 1/4 of the car you'll have cooler pads that will cut better, the foam in the pad won't overheat so the pads will perform and last.  And then if you clean them the same day with the fireball towel and pad cleaner (dilute 50mls to 500ml of water and spray),  and scrub with the rockcar pro pad cleaning brush, rinsing and squeezing to make sure they are clean and all the polish is out, then leave them to dry standing up or Velcro up so the water can drain out overnight, your pads will be clean and you won't get polish drying inside causing hard spots.  

Most people don't do this, they buy 1 or 2 pads, overheat them and don't clean them properly, then wonder why the pads don't last as long.  Look after your pads and you will bet much better results, faster, and your pads will last a lot longer.