Gold plating in software engineering, or project management, or time management in general, is a term used to describe the error of working on a project or task past the point where the extra effort is worth the added value. For example: after having met the requirements, the developer works on further enhancing the product, thinking the customer will be delighted to see additional or more polished features, rather than what was asked for or expected. The customer might be disappointed in the results, and the extra effort by the developer might be futile.
Gold plating is also considered a bad project management practice for different project management best practices and methodologies such as: Project Management Body of Knowledge (PMBoK) and PRINCE2. In this case, 'gold plating' means the addition of any feature not considered in the original scope plan (PMBoK) or business case (PRINCE2) at any point of the project since it introduces a new source of risks to the original planning i.e. additional testing, documentation, costs, timelines, etc. However, gold plating does not prevent new features from being added to the project; they can be added at any time as long as they follow the official change procedure and the impact of the change in all the areas of the project is taken into consideration.