There are many worms chickens can get, some that will never be visible to the naked eye until a necropsy is done on a dead chicken. I would say that if a person is going to take a "wait and see" approach then you need to ask yourself what, exactly, are you waiting to see? Worms in the poop? Scraggly, skinny, generally unthrifty chickens? Dead birds?
Deworming a couple times a year is simple, cost effective worm management. If one does not wish to go that route then at the very least consider doing regular fecal tests. Once or twice a year fecal testing is not enough, too easy to get a false negative if worms just aren't shedding eggs when a single test is done. But doing them on a regular basis should let you know if there's a problem. Cost with that method is generally a lot higher then simply deworming couple times a year.