There is an important advantage between solid state relays and other types of relays, such as electromechanical relays or contactors. The advantage of solid state relays is the deterioration of the internal parts of the relay since in these relays there is no deterioration as they do not have mechanical parts as in electromechanical equipment. 

The applications for solid state relays They generally include equipment that requires high cycle speeds, low acoustic or electrical noise, or resistance to vibration, such as equipment material handling, equipment doctors, teams of heating/refrigeration, control of lightning and bombs