Begin with one piece that sits close to what he already owns. A man with a steel watch may take to a white metal wrist piece; someone who wears a yellow gold band might like a neck chain in the same tone. Keep the first purchase understated. A plain chain, a slim bracelet or a simple ring is far easier to adopt than a bold statement piece, and you can always add more once the habit sticks.
If you are buying as a gift, look at his clothes for clues. Open collars and T-shirts leave room for a chain; long sleeves and a watch on one wrist suggest something for the other wrist.
Choose high polish for classic shine, brushed for a quieter look, and hammered if the piece is going to take a beating. High polish is mirror bright and shows fine scratches soonest. A brushed or satin finish carries fine parallel lines and a soft sheen; it reads understated and can be refinished when it wears. Hammered metal is covered in small dimples that disguise everyday scratches, which makes it a good match for someone who works with his hands.
Measure the necklace he already likes before you buy a new one, then choose the link. Rope and box chains look fine and tidy, while Franco and Cuban links have a heavier, bolder presence. The same link styles carry over to the wrist, so a chain and a bracelet in one pattern make a natural pair. Compare options in chain necklaces and chain bracelets, and check the clasp: a sturdy one is worth more than a fancier link.
For daily wear, 14K gold and platinum are the hardiest picks. 14K gold is harder and more scratch resistant than 18K, so a bracelet keeps its shape after months of knocking against a desk. Platinum is naturally white, dense and heavy in the hand, hypoallergenic for most people, and it develops a soft patina when scratched rather than losing metal. White gold gives a similar bright look, though its rhodium finish wears and will need renewing in time. If he leans warm, browse yellow gold pieces across every category.