The argument for reuse is put very well here (summarised in the extract below):
Reuse keeps goods and materials out of the waste stream
Reuse advances source reduction
Reuse preserves the “embodied energy” that was originally used to manufacture an item
Reuse reduces the strain on valuable resources, such as fuel, forests and water supplies, and helps safeguard wildlife habitats
Reuse creates less air and water pollution than making a new item or recycling
Reuse results in less hazardous waste
Reuse saves money in purchases and disposal costs
Reuse generates new business and employment opportunities for both small entrepreneurs and large enterprises
Reuse creates an affordable supply of goods that are often of excellent quality.