Screen Protectors

i applied a Zagg protector to a mobile phone a few weeks ago - it's a rather titchy process, and i managed to get an airbubble/dent on the screen protector that couldn't be removed. also some indentations of ball-point pen lines, where i had measured the cutting, then changed my mind. i'm sure a second installation would go much more smoothly and with less frustration-type growls now that i know what to expect, but that first time will be annoying.