Boba, I'm a an expert when it comes to frames. Why? Because I've literally had all of the above happen to me and learned the hard way.
Add that to the fact that I live in a relatively humid environment and you have a recipe for disaster.
1.) Use matting. I really don't recommend framing anything without it. The chemicals in the print can react upon contact with the glass and BOOM! Disaster.
2.) Use acid-free matting. If not, the chemicals in the print will react with those in the matting and BOOM! Disaster.
3.) Use U/V protected glass. Even if it's not in direct sunlight, the print can still fade. Yes, the glass is more expensive and no, you won't see anything until years down the road, but still keep it in mind. (This shouldn't be a top priority though.
4.) Get the back of the frame sealed. Again for areas with lots of humidity, you may want to put that higher up on your priority list. It's just a good way to keep the "bad" stuff (ie. humidity out.)
5.) Don't bother with spacers. They're a waste of money. Trust me. Trust me. Trust me. Stick with matting.
Bottom line: Humidity and print chemicals are your worst enemy. Respect them. And they'll respect you.
If you don't live in an environment with humidity, you've already won half the battle.
I've got my first Alamo Drafthouse poster coming, so I'm already looking for a suitable set-up. It costs an arm and a leg to do it right, which is my all of my autographs are sitting in my closet, meticulously separated from each other using acid-free paper. It's the only way I know they're safe, until I can afford to frame them properly.