Doing the right things right, the first time, on time, every time may indeed be our theme song. It likely comes as no surprise we are now singing that old song in reference to serious relationships. “Relate the best you know how, every chance you get.”
A truly serious relationship is not a now-and-then, if you feel like it or have time proposition. Neither is it a place where less than your best will do, unless you do not care about risking the relationship. Sure, that level of effort and commitment benefits your significant other. You do it for them; and that is certainly thoughtful of you. More to the point though, giving it your best shot every time is in your very personal self-interest. Do it for you.