Do you need to always count calories to live a healthy lifestyle?

No. Counting calories is not necessary to live a healthy lifestyle. More important is to get daily exercise of at least 30 minutes and eating in a healthy manner. This would include eating more fruits and vegetables, less processed foods, less saturated fats, more unsaturated fats, less simple carbohydrates and more complex carbohydrates.
No - you don't. Eat healthfully w at least 5 servings of vegetables & 4 of fruit /day (organic is best). Increase nutritional fiber. Avoid refined sugar & junk carbohydrates. Avoid sweetened juices, soda & caffeinated beverages. Watch portion sizes. No tobacco, illicit drugs & low to no alcohol use. Aim for 7.5 to 8 hrs sleep /night. Hydrate w at least 64 oz of water / day. Maintain good hygiene. Daily physical.