I've never changed the sights out on a gun before; whether it came from the factory with fixed or adjustable, I've always just left it at that. For the first time, for my G17, I'd like something different than the factory sights. My question is: what advantages, other than cost and resistance to change, do fixed sights have over adjustable? Must I have fixed sights (specifically for the G17) installed and sighted in by smith, or is it a DIY job? How the heck would you sight in fixed sights?