Screen protectors are a must. I buy the cheap ones from ebay and change approx every 4 weeks.

The trick to avoiding bubbles is making sure your screen is spotless before applying the protector.

If you look closley at the bubbles you will more than likley notice that the culrprit is a small piece of fluff, dirt or dust.

I also buy the cheap ones as i have to get it perfect with no bubbles or it annoys the hell out of me, that way I dont mind throwing one away if i get it wrong !!!