I used to only run servo horns. I love the way the car feels that way. But some tracks I need to run servo savers. Some of the small tracks I run on have large PVC elbows/pipes that stick out for corners. Not good for my servo if I cut too tight or get knocked into it. I've already replaced all the gears in my servo. I run the s9550. You would think it's the 1 plastic gear that strips. But actually sometimes its the brass gears. That costs $40 for the kit. I have plenty of plastic gear spares though. Also I've learned that if the crash is hard enough to strip the servo gears, it's hard enough to bend the steering linkage arms. I dreaded that with my EvoIV. I don't know how many times I've had to replace the steering linkage arms in that thing from running no servo saver. I do however only run a servo horn if the track has curbs or corner dots for corners.