Selecting the "best" denim depends on what "best" means for you!
Best Quality
Look for heavyweight denim with generally cotton and tight, reliable sewing. Selvedge denim and clean finishing are good signs. Consider trustworthy brands known for quality.
Top of the line retail stores, designer denim stores, or online retailers specializing in quality denim. Be prepared for a higher price point.
Best value
Good balance between quality and cost. Mid-weight denim with good stitching really looks at sewing and equipment. Look for deals or discounts at retail stores or online retailers.
Retail stores, a few online retailers, and even second hand shops can have unexpected, but invaluable treasures!
Most Sustainable
Sustainable denim brands that use natural cotton, reused materials, and eco-friendly manufacturing processes.
Online retailers having some expertise in sustainable fashion, or look for eco-conscious denim lines from laid out brands. Be ready for potentially higher prices.