While layers are not required for posing, sculpt layers can be useful when posing provided you keep the following in mind:

• Consider creating sculpt layers to store your pose work prior to beginning any pose or deformation work. Since the deformations can potentially modify your model so that it cannot be easily returned to its original pre-posed state, placing your poses/deformations on a sculpt layer (much like you would with sculpted detail) will let you return to the pre-posed state if required.
• Sculpt layers can also be useful for copying just the pose and pose related deformations made on one side of a model across its axis of symmetry so long as only pose data has been stored on the sculpt layer being copied. For example, you can achieve a symmetrical pose on a character despite the sculpting being asymmetrical if you use some sculpt layers for sculpting detail and others for posing (and manage them correctly). For more information, see Sculpt using symmetry
• Any posing applied to a sculpt layer is locked to the subdivision level it was created on. If you turn off a sculpt layer that contains posing, you will also turn off the posing for that layer.
• Joints and joint weighting can be used on any subdivision level. Sculpt layers are locked to a particular subdivision level, so you cannot pose using the same joint/weighting on a different subdivision level until you create a new sculpt layer on that subdivision level for the posing to be stored.
• Any layers that contain sculpted detail that are visible when a pose is committed must remain visible when posing is performed on that layer. Otherwise, existing sculpt detail may not appear correctly. This limitation becomes more evident when you turn off the pose layer and the sculpted detail is modified as result.
• As a result of posing using sculpt layers at lower subdivision levels, finer sculpted detail that was created on higher subdivision levels may not convert properly to the new space of the pose when you return to the higher subdivision level. You can work around this by ensuring you commit the pose on the highest subdivision level. All other actions (creating joints, posing joints, etc.) can happen at any level without problem. For further information on committing poses, see Committed vs. uncommitted poses.