It depends on what the truck is used for. Strictly offroading, of course not. Being driven on the road? You don't have to but reccomended. It depends on how bad the truck pulls too. Big tires are expensive and a little wear means big cost too.
if you have independent suspention front and rear chances are a 4 wheel alignment can be done typically front wheel drive vehicles but not all.
yes all cars and trucks need to get aligned at some point
You probably have worn steering and suspension parts causing the front end to be out of alignment.
Four wheel is preferred.
My van has bad tires at front and better ones at rear, should wheel alignment be performed with bad tires?
No, its Front wheel drive
Depends on vehicle and type of front end.
When you have the front end aligned the mechanic should align the steering wheel also. This is so the steering wheel is positioned straight when you're driving straight down the road.
That requires a front end alignment machine to do that.
NO That depends on how the struts attach to the knuckle or control arm. On some front wheel drives an alignment is required.
Some cars you can and some require 4 wheel alignment.
Assuming that one is referring to a front wheel alignment, there are a number of signs that can indicate that this process is required. If the car has driven over 100,000 miles since the last alignment, the front tires are wearing unevenly, the front of the car shakes when driving on a smooth surface, or the car is pulling to one side, a front wheel alignment is probably needed.