Ears and fingers complain first. The fastening on a cheap earring, or a ring that turns the skin green, is usually a mixed alloy with nickel in it. Taking the piece off every night does not fix the metal.
Stainless steel is the practical answer for daily jewellery. It is the same family of metal used where skin contact is constant. A gold colour on steel is a finish, not a brass core.
Shop hypoallergenic jewellery, and if earrings are the problem, start with the smaller hoops and studs in the waterproof edit. Water is a separate question, covered in showering in jewellery.