I swear by tempered glass screen protectors. If nothing else the edges don't slowly crumple up and come loose like film protectors. I have used one on my Zenfone 2 since I bought it and the screen is still perfect.
Read the reviews before you decide on one. I try to go with ones that come with the stuff to clean your phone screen before you install (alcohol wipes, lint free wipes, sticky tab dust picker-uppers, etc) as having a perfectly clean screen before you install is a must. Once the screen is cleaned installation is super simple so long as you take your time and make sure to line it up. If you mess up a decent tempered glass protector will come off fairly easily so long as you are careful. I have yet to have one damage my phone's screen.