Be gentle with your gems. Roll them on your wrist with care with the operative word being ROLL -- avoid excessive stretching when placing on wrist. Stretch bracelets are the easiest to wear and can last an exceptionally long time.
Keep your bracelets away from harsh cleaning chemicals, extreme temperatures, lotions, perfumes, soaps and anything that will react with elastic.
Avoid extended exposure to water and remove before washing dishes, showering and swimming.
Even with exposure they can and DO last an exceptionally long time.