For those of you who chose to use the Spigen Tempered Glass screen protector, here's a little advice in case you accidentally get some dust underneath the glass (where the adhesive is) or make a smudge underneath:
1. Don't panic
2. Hold the glass by the edges and go to the bathroom or kitchen where you can get a quick few drops of hand soap and water.
3. Spread some soap and water over the dust/smudge area. You can actually "feel" the dust with your soapy fingers.
4. Rinse the soap/water solution off the adhesive side (no worries - this won't remove the adhesive)
5. Carefully apply the glass over the phone again.
The adhesive is the same stuff that 3M and other companies use for their wet-apply screen protectors like invisible shield (Zagg) etc. So it takes to soap/water solution well. I've already re-applied a few buddies' glass protectors because specks of dust had gotten underneath. Hope this helps some of you. The tempered glass is an expensive investment but worth the protection - so I know making it look "invisible" is ideal. Good luck!