Cost of the kit,severity of the problem,my own frustration level at the time, my detetmination,all of these things factor in.I have slogged thru my share of kits,and have also tossed a few,feeling it wasn't worth the effort,so everyone basically has their breaking point.Although I suggest that some have the ability and the inclination to battle thru anything,but not me,I have a breaking point that varies.