How can you differentiate between addition and condensation polymerisation?

In Addition polymerisation, monomers generally join together to form saturated polymers. There are three steps to chain reaction to form addition polymer, they are initiation, propagation and termination. In condensation polymerisation, functional groups of two monomers react together to release a small molecule to form a polymer. Generally, small molecules like water or HCl are released as by-products.