Well, there is a lot of debate about how much planning, if any, is appropriate.
Do you need maildrops? No, there are always alternate ways to resupply. But, some places make it very tough to resupply. Now, the way to figure that out is to make a plan for resupply every 3 to 7 days. For example, how are you going to get through New Hampshire. Sure, stock up in Hanover. But, where is the next place to stock up? Read the Companion or Wingfoot and figure it out.
Another thing. What about maps? Are you going to carry 2000 miles worth of maps with you, or pick them up along the way. Assuming that you pick them up periodically, then you will need maildrops.
Do you need quality equipment? No, truefully. You see all different types of equipment out there. You see some with the high end stuff, others with Walmart, others with army surplus, and still others with antiques. The fact is that you need to get equipment that works for you.
Will you be OK with no plan? Well, I certainly suggest that you have a plan for where you are going to resupply next. After all, I doubt that you are going to show up with 5 months worth of food in your pack. Plus, your family and friends should have some idea of where you are, and where you expect to be when.
So, my advice is to make a baseline plan that includes all your resupply places, and how many days you plan to resupply for.
Peaks