If your exhaust is rusted through or the muffler is swiss cheese, yes changing it is necessary. Exhaust wears out. It's general maintenance.
If your truck has more than 75,000 miles on it, changing spark plugs is necessary. Spark plugs wear out. It's general maintenance.
Spark plug wires tend to last a bit longer than the plugs, but if they're cracking and hard/brittle, yes change them. Plug wires wear out. I suggest doing them when you do your spark plugs, but some people may find that as an uneeded expense....and premature replacement.
When I first read the title, I thought about "exhaust plug" and "exhaust wires"...