Redeco
A redeco is a toy which uses the same molds as a previously-released toy, but has been reproduced with different plastic colors and/or different paint applications.
For example: the first three Generation 1 Seekers, Starscream, Thundercracker, and Skywarp, are redecos.
A redeco uses exactly the same tools or molds as the original toy. If any changes have been made, even something as simple as giving the toy a different head or additional pegs for locking body parts into place, it is more properly categorized as a retool.
The term "repaint" is also in wide use among fans as a synonym for "redeco". "Redeco", however, is the term used by the people on Hasbro's Transformers team. Additionally, the term "repaint" is technically wrong in almost all instances of a same-mold-new-colors toy, as typically more than the paint applications are changed when a toy is redecoed.
Why Redecos?
The single most expensive step in making a Transformers toy is making the steel-cut molds required to hold then cool molten plastic. Combined with the salaries of the designers and engineers, and there is a very considerable expense involved in making a single toy. These expenses are for the most part not involved in making a redeco, giving the company a chance to make a larger profit on a single mold.
