I was looking at the list of non-renewable items the other day, and figured I'd make a blog post about whether or not these resources have a point in the game if other options are available, and if so whether or not they should be renewable.
Item #1: Gravedigger items
I did get a good laugh out of these when I first found them (back before the Insanity! update), although they didn't have a use for me because I could never live long enough to find the Pig King. Although they give quite a bit of gold when traded to the Pig King, and might (maybe to some) have cosmetic value, meats (eggs are especially valued to me because you can get it from feeding a pet bird Cooked Monster Meat) are renewable and make them ultimately obsolete. If you really need (or want) more gold, they are worth grabbing, though. I mean, EIGHT gold nuggets for a tub stopper? That Pig King is digging his own grave by paying you for this stuff... Heh, graves. See what I did there?
Item #2: Mandrakes
I never really figured out what to do with these little guys. I pick them, they die (I tended to pick them during the day). I don't pick them, they get eaten by something. The only real use they have aside from consumption (which can be a useful tool on occasion) is the crafting of the Pan Flute. Not everyone plays as Wickerwoman and as such able to make the Sleepytime Stories spell tome, and I'm positive that there isn't a logical soul out there who plays this game wanting to waste their amulet to put mobs to sleep. Not to mention that it doesn't work on some. Sleep Darts are a better alternative, since they require less Reeds, Stingers (both renewable and easy to get) and Crow Feathers (which are even easier to get).
As for their status as allied mobs, I am not so hopeful in that they are useful. They are weak, and also suicidal, attacking anything hostile they find while annoyingly screaming at you. I mean, they're just so annoying.
Item #3: Turf
Turf is everywhere. It is the ground you walk on. Let us note here that Turf has no real use, aside from burning and cosmetic use. Animals don't need it to live, nor do plants need it to grow. Pull up the ground beneath a Tentacle, it keeps on swinging. Dig up the dirt below a Grass Tuft, it grows back as usual. Not only that, but if you so happen to find a way to need enough turf, you will likely have enough to use before running out because there is so much of it in one world. And if this is still not enough, take the turf with you through the Wooden Thing. There'll be a lot more where that came from in there. If you need marsh turf, go underground and kill a Tentapillar. It drops the stuff. You can also craft checkerboard turf with marble and an alchemy engine, and we all know that marble is renewable in caves because of earthquakes and there are statues and trees made of it in the chess biome.
Item #4: Honeycomb
I love apiculture. It's a simple and profitable way to get nourishing food (like Honey Hams and Honey Nuggets) and medicine, whether it be painkiller or antipsychotic (Healing Ointment, Taffy and Pumpkin Cookies). Bees and their associated living quarters are useful. Unless you modified the spawn rate of Beehives, there should be no shortage of Honeycomb sources in your world unless you destroy every single hive. At that point, however, you can make so many Bee Boxes that you will never need Honeycombs again. The only other use Honeycombs have are for use as a substitute for Honey and a neutral filler. You already have tons of fillers that are both renewable and easier to get, and Honey is a lot easier to obtain and does not run out. In fact, having Bee Boxes will often give you more Honey that you will ever need. If you're smart with how you use your Honeycombs (for example, no Crock Pot cooking), you won't have a problem with this.
Item #5: Eye Bone
This one is pretty simple. Chester spawns from the Eye Bone. You only get one Eye Bone, and you also only get one Chester with it. Getting more than one Eye Bone (cheater!) will not get you more than one Chester. As such, the Eye Bone does not need to be renewable at all because if you find one and keep track of it, you'll never need another.
Item #6: Grass Tufts, Saplings, and Berry Bushes
These three resources are quite useful in the Don't Starve world. Grass and Twigs are two essential and very useful ingredients in almost every crafting recipe the game has to offer, or a pre-requisite. Berry Bushes give you food all the time (except during Winter), even if they can spawn Gobblers or need fertilizing. Getting enough of these three can pretty much guarantee you all the resources you will ever need, if you plant some Pine Trees too and have a cave nearby. It can be helpful to bring these through the Wooden Thing, but they are easily found, especially in Grassland biomes (the lands where you start your adventures that are littered with Flint). If you really need more, go look underground. They constantly regenerate what they provide, so if you have enough, why try to obtain more?
Item #6: Fireflies
Fireflies are useful. Appearing most often in Forest biomes, these luminous lightning bugs are often used as infinite standing light sources. They also, however, have use as Jack O' Lanterns, which can be smashed before they disappear along with the pumpkin to be reused again. Their only other use is to be made into Miner Hats, which are worn in the hat slot and provide light while allowing for hands-free operations. When depleted, a Miner hat turns back into the Straw Hat it was made from, and the shiny creatures used to make it disappear. A better option would be to carry torches when exploring dark areas. Night only lasts so long, and in caves there are multiple natural light sources that last forever if not depleted (that is why I don't pick lightbulb plands or chop mushtrees). There is also Willow's Lighter and the Slurper, if you find one and can handle its insanity aura and the hunger depletion it taxes you for its services.
Item #7: Wooden Thing components
These items have one use and one use only: To complete the Wooden Thing and journey to the next world. They have no other use in the Don't Starve world. There is no other Wooden Thing to complete, and if there were it would likely have the same effects as any other. If you don't plan to leave your world, you can use these for any cosmetic value they may posess, but other than that; this is it.
Based on these observations, excepting cosmetic value, the only non-renewable items one might want to obtain for extended use would be Honeycombs, Grass Tufts, Saplings, Berry Bushes, and Fireflies. All but Fireflies produce enough product to make it so more of them aren't needed. Fireflies, however, can adequately be replaced by Torches for nightly and spelunking purposes. In spite of this, however, the Firefly is probably the most likely non-renewable to have a reason for becoming renewable: Miner Hats.
EDIT: It would appear I forgot one: Gears.
Gears are indeed useful, but their use is limited. The first thing Gears are made out of is the Divining Rod, which tracks he location of Maxwell's Door and the Things. If all the things have been obtained, it is likely that you will be led to the Wooden Thing, providing more Gears if you can handle the chess pieces. This is probably the best use for your first Gear, perhaps obtained through gravedigging. Gears are used to make Iceboxes, which double spoilage rate (that means food and other spoileables take twice as long to go bad). Unless playing as WX-78, this can be quite a valuable tool, especially when winter comes. On the topic of that mechanical member of the DS character cast, Gears can be eaten by WX as an upgrade to his system. In addition to providing a good amount of points for all three 'circles of life' as I call them, they also permanently increase his stats. Enough of these bionic badboys can turn WX into the Chuck Norris of the robot world. His stats do cap, but only after they have gotten ridiculously high. Usually two or maybe three iceboxes are more than enough for most players, but when playing as WX, whereas spoilage is not so much of an issue, Gears can be used for very handy upgrades. Even so, most characters won't need that many. Maybe three or four, considering the player may make two or three iceboxes and one divining rod and is not playing as WX. And as long as you don't plan on lasting through Winter entirely on Berries.
Does anyone here think that any of the above non-renewables should be renewable? Voice your opinions below!