Why Photoshop Layer comps are a good thing
The bane of every front end developer's day is receiving a hastily put together Photoshop file, with unused exploration layers, layers with default names (Layer 157, anyone?) and general lack of organization. As the developer tries to identify which layers correspond to a particular webpage, the simple process of turning over creative files to developers can turn into a painful endeavor, delaying production and impacting timelines.
From a creative's perspective, organizing art files in a production-ready format is always a challenge. Client-driven demands put pressure on proper organization and cleanup of the files, resulting in an overall state only the original creator can love and understand. While some creatives manage to keep a tight control over organization of the file with layer sets and proper naming, there are shortcut solutions for times when this ideal approach is not feasible.
Proper use of Layer comps palette, introduced back in Photoshop CS, is one such solution. While it will not clean up your artwork and give every layer a meaningful name, it will make a programmer's job a whole lot easier. Located in "Window / Layer comps" palette, it is a snapshot of all layers and effects that need to be turned on to generate a particular web page. As you finalize each web page in Photoshop, create a new comp in "Layer comps" palette and save it, with a name matching that of a web page.
Once the file is complete, and all screens are assigned to individual comps, review each page in Photoshop by turning on one comp at a time. If everything looks good, your file is ready for production!