A packing list is the cheapest way to avoid buying the wrong gear. Start with the guide on writing the list before you open the cart: it helps you see what you already own, what you are missing, and which purchases can wait.
Then use the list that matches your trip. For trail days, the Ten Essentials guide explains what each category means in practice on a day hike. For hunting, the all-day ground blind guide covers what to bring for comfort, quiet and safety during a long sit. Read the general guide first, then the trip-specific one, and update your list after each outing.