Firstly I would like to say thanx to "jaklumen", "Sy_Accursed" & "D. V. Devnull" - your comments are well put and insightful. Also, "Slayer_Jesse" - thanx for the videos, especially pt 2 (very touching) - they made me think of things a little differently.
I personally think that each person who want/needs to quit gaming (whether it be RS or any other game) needs to look upon their own reasons, not just someone else saying "You should quit because....".
I am 43 and have been playing RS since 2005 (off and on - I have quit & come back a few times) - but my reasons for doing so have and always will be my own.
Now, speaking based on my own personal experience with RS (and based on comments from the videos posted by Slayer_Jesse) if you want to quit playing - or just take a break. Let your friends know - you don't need to say why, they will miss you sure - but they will also understand that real life takes precedence over games.