My boy must say "I love you" ten times a day. I must say it to him a hundred times a day. I think it's a really important thing to hear. It's important to know you are loved.
Knowing you are loved means you are not alone, it means that at the end of the day when everything is going wrong you are not alone.
A child that hears those words regularly from their parents, secure an attachment to their parents easier and quicker than those that don't, this in turn helps manifest into positive adult relationships in the future.
I don't think you can hear that lovely little phrase too much. Do not underestimate the power of those words. Say them as often as possible and to as many people as possible. Sometimes I feel awkward saying them to certain people, such as the older generation but if I feel it then I say it. I hope my boy grows up remembering how liberal I was with those words. I don't think you will find a child that says "my parents told me they loved me too much".
My parents and grandparents grew up not hearing those words from their parents. It just wasn't something you said then in general. That doesn't mean my parents are scarred for life but ask them if they would have liked to have heard it - I know what their answer would be.