It's very hard to put a definitive time interval on when the rigging needs to be replaced because it really depends on several factors such as salt vs. fresh water sailing, how hard you sail the boat (and with how many people on board), how often you sail, how hard you are on your equipment, will dismasting put you in a life threatening situation or just be an inconvienence?
Five years is a good baseline number, but for me, I will replace my rigging on my beach boat every 3 years. If I only casually sailed on a small, fresh water lake, I'd probably let it go to about 10 years (just inspect the rigging regularly).
As far as what specifically to replace, I personally replace all of the wires that hold the mast up at the same time- shrouds, bridles, upper and lower forestay since all of these wires are potential failure points. Shroud anchor pins should be inspected for bending. Toggles, adjusters, shackles, and clevis pins I don't replace unless clearly damaged.