You can think of bushings in a clock, as you would wheel bearings on your car. If the bearings on your car get worn the wheel will wobble. If they loose the lubrication they will not spin anymore. They are what support the wheels of your clock movement. If they get worn the wheels will not be in the proper position to operate properly. When the gears are not in proper alignment the movement will bind. When one gear is not in position it might run to deep in the gears of the next wheel. Then it will cause the clock to loose power and stop. If the bushing gets worn too much it can cause the wheel to release from the one next to it and then the clock is in the self-destruct mode. When the mainspring looses all its stored power the shock to the movement is catastrophic. This is not uncommon. That is why it is important to have your clock serviced every 5 years. This is the only way to keep the bushing from warring out. Once the oil in the movement losses it lubricating properties the steel pinions that support the wheels start to ware at the brass plates that support the whole movement. There are a few types of bushings in use. There are some that screw in, some that press in and the ones that the lazy people use that you lay on top of the pinion and soldier in place. These you can usually only use on early American movements that have long pinions that stick through the plates. The screw in bushings does a good job of fixing the problem. It is not required to take the movement apart to use screw in bushing. These types will save you money in labor since the repair shop won't have to take apart the movement. Press in bushing will maintain more of an original appearance in the movement. These types require the movement to be split. So in other words it has to come totally apart to put press in bushing in. So it will probably cost more. The screw in and the press in are the same when it comes to performance. Most shops charge by the bushing. Usually it will be about 20 dollars for the first and around 10 to 15 dollars apiece for any more that are required. Look at that back of your movement before you take it in. The pivot holes look like a hole with a pin coming out of it. If they tell you that it needs bushings replaced, ask to see which ones. A good shop will show them to you. If they tell you on the phone after a free estimate that it needs bushing, go to the shop and ask to see where they are needed. They should be happy to show you. If not you might want to think about taking it elsewhere. Once they show you it will be obvious that they are needed. You can see the slop around the pinion. Being in the army has given me a lot of opportunities to travel. I always try to get to the clock repair shops and ask them the same question. I'll tell them I have an early American mantel clock that I want serviced. I'll tell them that it is running but I want it cleaned and lubricated. The prices have ranged from 50 to 150 dollars. With some telling me that they will have to replace all the bushings. Yeah right! So arm your selves with this when you go to the shop. Don't get your clock cleaned, just the one on the mantel.