A car clutch is not a part that wears in the sense that it needs replacing regularly. A clutch lasts about 62 000 miles. However that depends largely on your driving style. A clutch kit wears more quickly in urban areas than on the motorway.
When your Bmw's clutch needs replacing, the clutch pedal can become difficult to depress or once depressed it won't come back up. In addition it can become difficult to change gears, or you might experience clutch chatter. When worn, the clutch can also start smelling.
At Mister-Auto.co.uk you will find Bmw clutch kits from top brands incuding Luk or Sachs. To find out which kit is compatible with your car, please enter the model and engine type into the search engine.