Friends are extremely useful in this game and it's easy to add more, even if you don't have real life friends playing Battle Breakers. Just go to the Social and start adding those recommended friends. Not only that you can use their heroes in battle in most cases (sometimes giving you massive bonuses and advantages), but you can also receive all sorts of gifts from them which help you progress faster. Remember to send gifts as well (the game will remind you daily) and set your best hero as the one that you share with friends - this can also be done from the Social tab.