Any SCH around here that is above a 20' is nothing but troubles. Knife heads break, splice bars pull apart, really frustrating.
Ours is on a 20' head, never broke the knife head but had the bolts break on a splice before but that was mostly on our 820 head, so far the 1020 is going better but we keep a set of metric tools, spare splice bar, plenty of nuts and bolts, and a box of sections in the combine cab so we aren't wasting time running back to the place to get everything.
Should add that if you find any loose sickle sections might as well replace them and the bolts holding them down on the spot, once the hole gets slightly oblong in the section they will break the bolt even if tight, its just a matter of time, and if its one over a splice the rest of the splice bolts break with it.
If you take the time to check them over before starting for the season and on rainy days some of the problems can be avoided. Any brand of sickle will have its own problems, knowing what they are is half the battle in my opinion.