What take into consideration when choosing jewelry wire

Select a Wire Gauge
Use gauge 20 or higher for earrings and wrapped bead links in bracelets and necklaces.
Buy gauge 18 to 20 for making most bracelets.
Get 16 to 18-gauge wire for making necklaces. Remember that 16 gauge is very large and difficult for most beginners to work with.
Decide on Wire Hardness
Use soft wire (hardness 0 or 1) for making spirals and round shapes.
Choose half-hard wire (hardness 2 or 3) for designs that require sharp angles, or where the wire must wrap around itself.
Buy hard wire (hardness 4) for beads jewelry that must stand up to a lot of wear and won't have any round shapes.
Choose a Metal Type
Use gold wire for aesthetics if your budget allows for it. Gold-filled wire is less expensive and looks and wears like gold. Both are tarnish resistant and come in soft or half-hard. Gold-plated wire is made to look like 24K gold, but the gold will wear off eventually.
Get silver wire for the look of it, but remember that it does tarnish and must be cleaned regularly. Silver-plated wire is inexpensive, but the silver can wear off, and it tarnishes also. Sterling silver is available in soft or half-hard.
Buy copper, brass or other less-traditional wire for its strength, looks or durability as necessary for your project.