The Inca Trail is a 25-mile, four-day hike. Because of overuse and damage to trails, Peru limits hikers on the trail and requires everyone be led by a professional, licensed guide service.
When looking for guide services, determine whether you will carry your gear, if any dietary needs will need to be met, and if you will have to share a tent.
Guide services will provide you with food and tents. You'll need warm clothes, raingear, good shoes and a sleeping bag. You might want your own familiar snacks, water filter (or purification tablets) and first aid kit.
Many tour companies donate a portion of their proceeds to help the local community or environment. Make sure your guide service treats its porters fairly.
Don't begin your tip the day after arriving in Cuzco. Adjust to its 10,910-foot elevation to avoid altitude sickness along the trail.