I bought all cart only starting out, and man it sucks finding boxes and manuals.  I would tell you to get the CIB now, you will be glad later own.  I have been lucky finding them, I haven't paid more than 1.50 for hardly any of the ones I have, and I am nearing having a full CIB set now.  CIB is a way better route to go man, especially if your into collecting for the long term.

if you have the smallest idea you may want a complete set  i would go  for complete games ..yes  trying to track down boxes and manuals is very hard and you end up paying a lot more in the long run..I started going for a loose collection but once i got all the carts i decided to go after complete and ended up buying a lot of games complete just to get the box or manual..plus complete games look so much cooler on the shelf 

I don't actively collect boxes, and I only incidentally collect manuals (when they pop up, I get them, and I keep them archived). I have a few boxes on display that look nice, but it's part of my set-up, like my lego Mario sprite and my console boxes...I'm not a completionist in that respect, just a nintendo collector and lover.

That said, I'm not worried about completing my loosey set, then deciding to go back and get boxes. If I want to complete later, and wind up buying CIB games I'll just resell the double carts.

Long story short...I get as much as I can, and I don't resell anything that's not a double. Accessories, boxes, whatever...I keep it. Because what sucks worse than passing up an opportunity to get a complete game when you're only collecting loose...is siezing the opportunity, then getting rid of the extras...and regretting it later.

You may wish to consider how you will define a complete collection. Some carts are available "cart only", like test carts. And are you willing to spend the thousand bucks for the couple of CIB's that can hit that price.....or always saying "almost a CIB collection" forever. I collect cart only. I have hundreds of books/boxes stashed away, but never even try to get the CIB. And it gives a looser freedom and ease to enjoy the collecting part. There are definitely two ways to collect!

I think I am going to take the middle road. Mostly carts with classics and rares in boxes when I come across them. You guys are right there is no way to ever have a "complete" cib collection that is "MINT". I also like the carts perfect so Id imagine even creases in the boxes would piss me off ... lol Oh and sealed isn't an option for me .... I like to know whats in the box it would drive me mental. 

i think it mostly depends on your wallet size and what you want to spend.  sure we all want the boxes, but its too damn expensive for me.  if i see a box in the wild, i will keep that one and sell the cart i already have.

I tell you what.  You can't play a box.  That is just how I look at it.  I would consider myself a quasi avid collector and the vast majority of my games are cart only.  As of today, after a good find on Rainbow Islands, my collection stands at 317 games and several accessories.  It comes down to what you are into.  Is it the love of the games or the love of collecting games?