However I do understand what you mean. I do not obsess over it at all however, i do everything i can to avoid any damage..
... having owned every iPhone since the first one... im happy to say Ive never damaged one at all.
How? its easy.
Firstly, as an adult with average motor skills (!!) I have never dropped my phone - this is a subject of some consternation between my friends and I as their phones are all scratched and dented and damaged through various droppings .... but I just dont get it... when the phone is in my hand I apply the appropriate level of care and grip and have never dropped it! They all think im weird to have never dropped it but how and why would you drop a £1000+ device?! - care and attention is a given.
Anyway, that said...
... when I first open the phone from the box, I always have the new case, and screen protector to hand. The screen protector is applied the moment the cellophane comes off the screen so it remains pristine and the case goes on.
Through the life of my phone I occasionally remove it from the case to remind myself what it's supposed to look like... and to slightly envy those with the relaxed attitude to carry it round naked.... I dust it off.. remove any debris that may have made its way into the case (and hope that debris didnt harm the phone) and put the phone back in its case.
Now, every time I trade in my phone, some lucky person is getting a pristine phone.
BUT - getting to the point - as much as I look after it.. should a tiny mark appear... because I know theres nothing possible I could have done to prevent it more than I have done... and the fact I use my phone all day every day - I am comfortable with that.