I wear mine as an everyday watch. Don't even take it off at night. Have done so for 5 years with my SMP, only very rarely swapping out to one of my other watches. During that time, my home was hit by a tornado and I wore the watch through most of the cleanup work and portion of the reconstruction and remodelling that I did myself. Only took it off when doing excessively hard work like hammering, chopping or moving furniture. No scratches on either the crystal or bezel so far.
Honestly, these watches are made to take more than just normal life. Sure, you can screw up anything by accident. No watch is unmarrable or indestructable. But the truth is that the SMP holds up very well, so you should not unnecessarily worry. The sapphire crystal is extraordinarily hard to scratch. The bezel isn't easy to scratch either.
Pretty much takes scraping against something like granite, concrete or a rough metal edge (like a nail or screw head) to scratch either of these materials. Nothing on the SMP is any more fragile than any other luxury watch. The only limitation is that the black or blue bezels cannot be buffed out like a plain metal one would.
Don't really know what to think of the couple of people that reported scratching theirs by simply bumping into a wood desk or door frame. I think these people are underestimating the force of the simple 'bump' or are just noticing earlier damage and attributing it to the wrong incedent. Mine has taken a hell of a lot worse hits than that with no marks.
