For day hikes, choose a lightweight daypack (15–30L). Multi-day trips require larger backpacking packs (40–70L) with supportive frames and adjustable fits. Technical activities like climbing benefit from minimalist, durable packs, while travel-focused luggage often features wheels and compartments for easy organisation. 

Select capacity based on trip length and gear: 20–30L for day hikes, 40–50L for weekends, and 60L+ for extended expeditions. Ensure the pack fits your torso length and hip size, as a well-fitted pack distributes weight comfortably and reduces fatigue on long journeys. 

Look for adjustable back systems, padded hip belts, ventilation panels, hydration bladder sleeves, rain covers, and multiple compartments or pockets. Technical packs may include gear loops, daisy chains, and removable lids for customisation. Durability, weather resistance, and weight are also key factors to consider. 

Internal frame packs hug the body for stability and are ideal for uneven terrain. External frame packs provide better ventilation and are suited to carrying heavy, irregular loads. Frameless packs are ultralight but less comfortable with heavier gear, making them best for minimalist adventures. 

Measure your torso length and hip size, then adjust the pack’s straps, hip belt, and load lifters for a snug fit. The majority of the weight should rest on your hips, not your shoulders. Try on packs with weight before purchase to ensure comfort and stability.