For 22LR (rim fire) I check the firing pin/hammer mark to determine impact force was sufficient enough to fire the round, then I rotate the round and attempt a 2nd or 3rd firing. If it still fails to fire, I pull the bullet, discard the casing and save the lead. If there are light impact marks I save the round, clean the gun and check for wear.

Although I have never had a problem with center fire ammo not firing, they would go into my reload bin where I eventually strip down the round, replace the primer and reload.