How long it will take to replace your roof will typically depend on complexity of roof, but let’s say you have a fairly walkable roof 6-8/12 pitch and not many transitions. A typical 4-5 man roofing crew could complete about 2,000-3,000 sqft worth of asphalt shingle removal/tear off and installation in a day on average. Your roofing representative should be able to give you a better idea of how long it would take.