I have a charging cable on my bedside table, so without thinking connect phone to cable before crawling into bed. Wife does the same with hers and charges her iPad and iPad Mini overnight too. So the question of how long a charge lasts never comes into it. We just need to know that when we start each day everything is ready to go. And yes, I do know from an engineering standpoint it is good practice to fully discharge a battery to keep it in good health
But I upgrade my phone every three years or so... and the battery still works fine at that time.
And surely how long it takes for you to discharge your phone is dependant on how much you use it each day? Mine gets a lot of use.