oneounceload is quite correct with his "Some guns seem unaffected by dry fire without them, some ARE greatly affected by that practice"
But, you don't have to practice repeated dry firing for damage, just store the gun with the hammers cocked. Been there, done that. Perazzi hammer spring $44, snap cap $6 -- you do the math.
When dry firing, it's not the spring that gets damaged but the firing fin. The force that would be absorbed by the primer is applied to the pin shoulder. I recall a crusty old sergeant warning that dry firing an M-1 could crystallize the firing pin. My S & W Model 52 Master target pistol has a device, activated by the safety, to allow dry fire practice. It rotates a metal stop between the hammer and firing pin