Difference between recorded and live session

The difference between this and a recorded session is that you can o multiple takes and then in the mixing stage use the best parts from each take. You can also add more effects like delay, reverb and compression to get the best sounding product. It is important to get the best sounding product as the client is expecting a good quality service for what they are paying for. However if you are doing live sound you can add live effects but there is a potential for distortion and unnecessary noise for accidental touching or bumping of microphones and other equipment.