Hi
I personally think that we have to practice the love-kindness exercises every day because that the way that we can give a good treat to every one because we are going to start being gentle and appreciate more the reason that we live to give love to others. 
we can help many people with this exercise because we are going to be prepare to motivate them to have a positive way to see their live and to be gentle with other people, family, co-workers and many others.