Sterling silver and stones will last your lifetime with a small amount of care.
Silver is a soft metal, so store each piece of jewellery separately in your jewellery box to avoid scratching - soft cotton handkerchiefs, jewellery pouches, tissue paper will keep jewellery from damaging each other, and decreases the tarnish on your silver. You may prefer some natural patina on your jewellery but if you like it to gleam, wipe it with a silver cleaning cloth when you take it off to store it.
Turquoise, lapis, and many of the stones in our jewellery are porous stones, so they should be kept away from oils, detergents, and perfumes as they may alter the colour and texture of your stone. Don't wear your jewellery until after you've put on your perfume and make up or while your soaping your hands - and don't dress up in jewels to do the cleaning!
Polishing pastes and cleaning solutions will alter the colour of porous stones so it's best to avoid them - the best method for buffing and cleaning silver is a polishing cloth with jewellers rouge. If in doubt go to your jeweller.