Looking after it between visits.

Most of what shortens a piece’s life is ordinary and avoidable. None of this needs a product you have to buy.

Cleaning it yourself.

Warm water, a drop of dish soap, and a soft toothbrush will do almost everything a jeweler’s machine does.

Soak, then brush gently: A few minutes in warm soapy water loosens the hand cream and soap film that is dulling the stone.
Brush behind the stone as well as the front: The underside of a setting is where residue collects, and it is what makes a diamond look flat.
Rinse over a bowl: Obvious once it has happened to you. Plug the drain, or rinse in a bowl.
Dry with a soft cloth: Use a soft cloth. Paper towel scratches softer metals.

Rarely a dramatic event. Usually something repeated for years.

Chlorine and bleach: Chlorine attacks the alloys in gold over time and can weaken the metal holding a stone. Take rings off before a pool or a hot tub.
Sunscreen and lotion: Harmless to the metal, but it is the single biggest reason jewelry looks dull on vacation. On Maui this matters more than most places.
Sleeping in it: Bends thin bands and loosens prongs slowly. A dish by the bed solves it.
Storing pieces loose together: Diamond scratches everything, including other diamonds. Separate pouches or a lined box.
Ultrasonic cleaners at home: Fine for some pieces, genuinely risky for others: emerald, opal, and anything already loose. Ask before you buy one.

Bring it in. Cleaning and a safety check are included on anything bought here, for as long as you own it.