Mold release agents serve two basic purposes. They act as a parting agent between layers of resin and the mold surface, so that cured parts can be removed without damaging the part or the mold.
When applied properly, mold releases help create a durable, high-gloss surface finish for finished parts.
They are light, non-toxic, and have good compatibility and dispersion with the resin system. They help to preserve the integrity of your part and avoid damage to both the part and mold. The effort required to apply a quality release agent during preparation far outweighs the hours spent correcting damage later.