My situation is like
@Buddy1969 's.
I bought a flip case for my Windows Phone as a compromise between function and form and loved it and so when I bought my v30, I immediately bought myself another one (different brand) and haven't looked back since!
I'm a big fan of cases (especially crystal clear ones), but not so much a fan of screen protectors - not even for my Nintendo handhelds.
I know the sticky residue days and easy mis-positioning days are mostly over, but I just don't like the feel and I have a light touch besides and so that's why screen protectors are a bit of a function-related issue for me.
I actually see some minor scuffing as part and parcel of using things like mobile phones which are all but necessities nowadays. Obviously, completely unscathed is preferred, but I'm good with some minor shows of wear, too, because I see it as natural.
That said, my v30 in its flip case (I love it) hasn't taken any facedown falls and hasn't been accidentally subjected to any onscreen jabs or pokes or rough rubs and
is still looking clear of scuffing under LED and fluorescent lighting.
Related to the discussion about future reselling (which I have nothing against), I'm something of a collector and I use the 'Like New' description header very sparingly when selling unless it's something very obvious.
I figure that if it's been used at any point of time besides for just a moment (like unboxing and then immediately returning it back into the box), it doesn't qualify any more for 'Like New' and instead, I tag with 'Very Gently' or 'Gently' 'Used' and then use a lot of photos and describe its use.
When I shop, I also don't hesitate to shop from people who tag like I do so there's that, too.