What you need to use all depends on your skin type. Exfoderm is recommended for dry and sensitive skin types because its primary ingredient is Phytic Acid, which is capable of gently exfoliating your skin without causing any skin irritation.
Exfoderm Forte, on the other hand, is recommended for those with oilier skin types because its primary ingredient is the tougher Glycolic Acid, which deeply exfoliates the skin and may irritate sensitive skin types.