Pls check refrigerant level first

Under-charged/over-charged system can make the compressor work too hard. The piston inside the compressor will wear out sooner. If the noise has started recently, it may be a sign that the piston is a bit worn. There is really nothing you can do about it. The efficiency of the whole system will be lower, but probably not to a point that you need to replace the compressor+coil.

For checking the refrigerant level on your own, please follow this video. 

Just my 2 cents, not advice from 大牛.