Yes, you come to relax more as you have your chickens longer. I've had mine around nine years, and the learning curve with chickens can be pretty steep. Those first couple years, I was making stupid mistakes that ended up killing some. For example, not knowing that chickens can't resist drinking from puddles, I ignorantly used insecticide in some planters, watered and lost a hen after she drank from the puddle under the planter.
Learning to tell when your chickens are sick and treating them instead of missing those important symptoms and having them die is another one that experience definitely helps. Learning the difference between sick poop and normal poop is another early warning sign that a lot of novice chicken keepers miss. Many of these things you just have to pick up as you go along, and you gain confidence the longer you have your chickens.
Another worry chicken keepers have is predators. Learning what predators are likely to be a problem in your area will help you to design safeguards into your coop and run so you won't have to worry about that, enabling you to relax more, even when you're on vacation.