Equipping the gears is one thing, but enhancing them will be an even bigger thing because it will probably end up using all of your Gold. Either way, you should still try to do it because it will affect all of the gears which you will equip in the future. Basically you will need to head on to the Equip tab and there you will see (when the option is available) an Enhance button below the gears which will let you upgrade the said gears up to a certain level. Whenever this becomes available, I suggest that you do it, because the equipment will stay strengthened and it will affect all of the gears which you will equip in the future - so it's definitely something that you should do, even though it's pretty much a Gold sink and you will end up spending all of your money.