I recommend screen protectors to any and everyone, as they are a rather small investment, that can prevent HUGE issues. If you ever wipe your screen for any reason, as long as there is dust present, it is making fine lines(scratches). They may not be visible to some, but they are there.
Anytime I buy a device, I have the SP ready to go, and the only thing I'll do before hand is check the functionality of the device, and once I know everything works, the SP goes on ASAP! Every cell phone I've ever had, has had one, as my phone takes a decent beating going in and out of pockets, and once I buy a new phone, I remove the protector, the phone is like new, and I sale it for top dollar.
If a person doesn't really care about imperfections, or just average wear and tear, you probably don't need one, but for anyone who wants to keep their investment in the best condition possible, buy a screen protector. And for those of you who want the ultimate protection, I recommend the full body wet install protectors from places like Skinomi, as those are the best, but require a decent amount of skill to apply, but work the best overall. I haven't used those "glass" ones yet, but I hear good things.