I admit I haven’t been a big mold user. In the past I haven’t done a lot of sculpting and most of the base shapes I use are simple enough that I can use cutters and shape by hand quickly and easily. For some crafters the use of molds to build inventory up is more useful: you cast an original in your mold material of choice and then create a series of pulls from the mold. Often, each pull is altered a little anyways so you have a whole new series of originals.
Instructables has a tutorial about using Composimold (a reusable molding medium) for helping with production work. The artist goes on to alter the pulls from the mold depending on what they’ll be used for.
How do you use molds and mold making in your claying?