Big Three

When doing any sort of overnight trips, backpacking or thru-hiking, the gear you should focus on is the big three. Backpack, tent and sleeping bag. It'll be what keeps you warm, comfortable and protected. It'll also be the biggest expense and were you'll have the bulk of your base weight (everything but consumables).

Gone are the days of 8 pound packs and even heavier tents. You don't have to go ultralight, but all the weight savings you can get while staying on budget and still maintain comfort makes hikes a lot more fun.

The heavier everything is, the more effort it takes. More calories burned and less maneuverability. It's a dance of weight and comfort. Pocketbook too.

Backpack

Resting on your shoulders and straddling your waist for hours a day, your backpack should be comfortable, capable of holding everything and not be overstuffed or too empty.

Sleeping Bag

It needs to keep you warm. Depending on the season, it could be a light blanket or a 0° bag. Even silk liners might be needed.

Tent

A tent needs to be big enough for you and your stuff. It also needs to be able to handle the season your in and the area you're hiking. Some use poles and are freestanding while others utilize your trekking poles. A bivy sack is a solo option if you don't care about space and want the most compact and lightest option.

We'll cover these more in detail. Apart from shoes (another whole can of worms), the big three should be the most thought about gear in your kit.