Yes. One of my pet peeves is ever at a friends place and see discs strewn about or even used as a coaster (!) You spent $20-$60 on a game, if you're not going to take care of it, sell it or give it away, don't damage it out of neglect.

Also, I like having mine organized on shelves in alphabetical order by platform and cases are great for that.

Well, with CDs you take the risk of scratching without case, and with cartridge you take the risk of losing it somewhere. And even if you have a special case for multiple CDs/cartridges, it's just easer to keep the case that came with the game.

Of course.I mean, why would I throw it away?It dosent make sense.

I always keep my game cases. Even for cartridges.
If it´s a paper box and it´s damaged, I buy a plastic box and cut the original box to be used as a label.
I prefer to keep the cases simply because I think it´s a better way to organize/identify the games, and it feels cooler to have your game shelf with all those colorful boxes than just those gray/black cartridges lined up.

i always keep stuff i paid money for

If it's Blu-Ray, it's scratch resistance.

Yes, need to put the games back somewhere :p

*shudders* casuals v.v

I never got rid of game cases, except maybe when I used to have a SNES.