Friar Lawrance is telling them that they need to enjoy each other slowly and not love each other too much that they burn each other out and get bored of each other. I think that this is good advise in the unlikely chance that they both don’t die that is. Because hes telling them to be in the marriage for the long haul. But, there is no long haul. so for all of us this is great advice that we need to admire things little by little and not over use or over due yourself. And no… Romeo and Juliet do not take this advise.