Helmets are headwear that provide protection against damage from spikes, players, mobs and fires when equipped. However, they don't help reduce the cold, like the chapkas - this means players have to sacrifice one advantage for another by wearing headwear.
Helmets are generally used for combat, especially since they seem to protect more against other players as opposed to mobs. Once equipped, there is a timer of several seconds before you can de-equip the helmet. This is something to keep in mind in PvP or hunting, especially in the cold winter biome.
The Wooden Helmet is the lowest tier of helmets, and provides the lowest protection out of all helmets.
Unlike all the other helmets, a workbench is not required.
The Stone Helmet is the second lowest tier of helmets, and provides the second lowest protection. It doubles the protection a Wooden Helmet gives you. They are useful, however, at times, especially in the earlier stages.
The Golden Helmet is the third tier of helmets, and provides considerable protection. They can be advantageous especially when fighting other players without helmets.
The Diamond Helmet is currently the middle tier of helmets, and provides strong protection.
It takes 1 minute to craft the diamond helmet, therefore it is recommended to have an IKEA Manual or full health and cold bars before crafting the diamond helmet. It would also be wise to check your surroundings for mobs and/or hostile players before crafting.
The Amethyst Helmet is the fifth tier of helmets, and provides a very strong protection.
Since it takes 2 minutes and 20 seconds to craft the amethyst helmet, it is required to have an IKEA Manual in hand before crafting in order to survive the crafting time. It would also be wise to check your surroundings for mobs and/or hostile players before crafting.
Players are required to have to IKEA Manual in hand before crafting in order to survive the long crafting time. Again, checking for mobs and/or hostile players would be a very good idea.