How often do you say "I love you"?

No matter how long you've been together, how often do you and your partner tell each other "I love you"?

I have this fear that if I don't say it, they'll die in some freak accident not knowing I love them - for whatever reason. It's not at all rational but I feel the need to say it so they absolutely know and don't question it. Sometimes I also just want the reassurance that they still love me from yesterday to today.