its good to know the anatomy of an airplane.i build almost all of my airplanes,so repair isn't that big a deal.some damage,say if you make an accordion out of a fuselage back to or past the wing saddles you might conceder ordering that section,unless you are pretty good at scratch building and have the Patience.the most common damage i have seen through the years wasn't too hard to fix,landing gear a smashed leading edge.broken vertical or horizontal stabilizers.some of the minor difficulties for arf's type airplanes is finding the color match covering.anything can be repaired on these RC airplanes if you are willing,like someone here said don't be afraid to try.