I have noticed that quite a few of my friends are very low levels in helping friends though they are 30+ players. I think this is a huge mistake. Strength is given daily to help friends and should be used! Will I spend diamonds to get more strength? Ermmmmm no. But I do use what is given often during the day. Because of that I am lvl 22 friend. That means I get to visit 22 friends and each one gives me 100 coins, 50 exp, 5 runes and a battery. That adds up to be a whole lot! Take the time to be a good friend, it's worth it
