The DT11 comes with a box of spares, that in my case included 2 firing pins, 2 firing pin springs, two leaf springs for the trigger unit and a few beads. I haven't broken anything (yet) but almost lost the screw for the adjustable trigger once on its predecessor. Worth a drop of loctite, or even keeping a spare. I was lucky that someone else spotted it on the mat, but it's something I now check for tightness when cleaning. Ejector springs and their little pushing rods might not be a bad idea as they can jump out if you are clumsy in removing the ejectors for cleaning.