Guide:Renewability

All Resources are Infinite
Resources only differ in their scarcity. Even though in a created world the amounts of certain items appears to be finite, i.e. number of gold ore tiles, while other resources grow back, spawn randomly or can be otherwise replenished, generally all items can be transferred between worlds and between characters and thus there is no theoretical incentive for saving up, rationing or hoarding items or materials. Rather a player can choose to gather and produce materials in bulk, or collect and craft items as required, while discarding anything that is of no immediate use. At any time a new world can be created and all its treasures and minerals gathered, the character's Inventory, Safe, and Piggy Bank are shared between different worlds.

Wood
Wood is arguably the most common and renewable resource. Chopping down Forest and Hallow Trees frequently drops Acorns that can be planted to grow new trees. It can also be found growing up by itself on jungle blocks (creating an artificial jungle is a good way to harvest wood without using acorns). Trees that are in the Corrupt, Snow, and Jungle biomes do not drop acorns. It is rare, yet possible, for surface Giant Glowing Mushrooms to drop an acorn.

Wood is one of the most versatile resources as well, as it is used in both construction and crafting:


 * Wood can be used for both building structures and background walls.
 * Wood is used for creating Torches and Wood Platforms.

Sand
Sand is an infinite resource if you have patience or the equipment:


 * Antlions can be goaded into generating more sand, albeit very slowly.
 * A Sandgun used with ammunition-conserving equipment, such as the Necro Armor set, can produce infinite sand.

By extension, Ebonsand and Pearlsand are also renewable, since the normal variant can be intentionally transformed prior to harvesting.

Cactus
Cactus is an infinite resource as long as there is 1 layer of sand, since it spawns automatically. Cactus can be harvested with ease by just removing the 1 sand block below it and sold for money or crafted to potions.

Glass
Glass is indirectly renewable because it is crafted from Sand, which can be produced infinitely.

Crafting Materials

 * Main article: Guide:Gardening

All plants are renewable resources because they can be replenished by seeds, or grow naturally in their respective Biome.

Demonite Ore is a renewable resource as it is dropped by Eye of Cthulhu and Eater of Worlds.

Meteorite is spawned randomly with a small chance of "falling" each night and a much larger chance when actively smashing Shadow Orbs. Meteor Heads spawn near large concentrations of meteorite and have an approximate 1 in 50 chance of dropping a chunk of the ore when killed.

Fallen Stars will frequently fall from the heavens during the night.

Obsidian can be produced without limit in an obsidian generator by exploiting the liquid physics bug.

Gel is renewable and can be easily stockpiled by hunting slimes or simply using a grinder mechanism based on the Slime Statue.

Obsidian generator
Obsidian can be harvested by creating a generator. A generator is an exploit that allows the infinite creation of lava and water, to create obsidian. Liquids in Terraria can be duplicated in this way because of a game mechanism in which a full bucket will always produce one full block of liquid, while less than a block of liquid is required to fill the bucket.

This video contains a detailed explanation on how to set up the machine. (instead of just using two blocks on the lava duplicator use three or four, this will allow you to click faster like the water duplicator. since the lava will spread out faster instead of taking a bit longer to actually fall off the block)

With the introduction of mechanisms such as Pumps, wire and timers in 1.1, it is now possible to construct an automatic obsidian generator, which does not require using buckets to repeatedly refill the lava or water vats.

A sample set-up of an automatic obsidian generator can be found here:

Video detailing the construction of a fully automated Obsidian Generator using vats and pumps.

Flooded Hellevator (strategy from LachlanInc)
Another way to make lots of obsidian without going to and from the Underworld is to make a Flooded Hellevator. This works well if you have a cave with LOADS of water pools. If you do just start a hellevator above the water pools and start digging downwards. Yes, I know in Minecraft the #1 rule is to not dig down, but if you have water with you, you're safe. Eventually, as most players know, as you get closer to the Underworld you will find lava instead of water (the place with lava pits don't alter the water with you into more lava, which is a good thing). As the water collides with the lava, you will get lots of you-know-what (obsidian). While making a Flooded Hellevator (by accident), I have discovered that caves have 2 sections. 1) The water section and 2) The lava section, which is closer to the Underworld. Sometimes liquid (I can't say water or lava because they are mixed) pools can be naturally formed ACROSS the gap between sections, making natural obsidian.

(found while making a Flooded Hellevator)

If your Flooded Hellevator collides with a HUGE lava pit (see next picture), you might as well have your own money maker!



(this screenshot was taken during a Blood Moon) If you are going to take my advice, here is what I recommend: Extra recommendations from Thirdy2:
 * Scuba Gear
 * Lucky Horseshoe
 * Cobalt/Obsidian Shield
 * Water Walking Potion/Obsidian Skin Potions. Just in case. Drink this especially if you have a habit of digging directly down.
 * Lava Charm/Lava Waders (if no other option is available, read below)
 * Not digging down on Obsidian. (No really, I have unfortunately experienced this)
 * Gills Potion (for the water).