what does your customer really want..?

Before you can decide whether your product quality is up to scratch you need to know what your customer really wants.

This is done via the product spec. Before the project timescales are defined and before the development stage the product spec needs to be defined and agreed with the customer. This needs to be done using a controlled document which is signed off by both parties. Following this any proposed changes from either side has to be agreed in writing.
This has a number of advantages:-

1) The customer defines exactly what they want.

2) The supplier clarifies its limitations.

3) Any ambiguity is removed from the process.

4) Spec creep is minimised; this is where the customer regularly tightens up or expands the original spec.

5) The project timescales are defined by the agreed spec.

This process is earier said than done and it is the Project Managers responsibilty to ensure the spec is agreed before development starts.