If you feel for someone tell them. It's too late when they've gone.
I obviously agree with the sentiment. I try to make it part of my daily actions, not to say it but to demonstrate it. I don't want to wear out the words by using them too often (I love my hairdresser, the production designer, the key grip - what's a key grip? and as for 'best boy', well, the mind boggles....)
Just a point though - we all gotta go sometime. There's always a last time for everything. Don't live in fear, don't obsess with rushing to the bedside to say all those things you meant to say. Give loved ones credit - they can know without it always having to be said, or texted, or tweeted.