In Minecraft, there are many resources you are going to want to draw on. It is a good idea to be aware of what they are, where they can be found, and how you can get more.
Most resources in Minecraft are not renewable. Once you’ve dug up some dirt or stone or ore, that’s it. You’re not going to find the material respawning there anytime at all, unless you’re on a multiplayer server whose moderator regularly goes around doing that on purpose.
A few, however, are renewable.
First- the non-renewable resources.
Ore is not renewable. The deeper you dig and the closer to lava or bedrock you get, the more ore you will find. Ore veins frequently run into or near one another, so it can be advantageous to carve out a large area around any ore vein you find. This is especially true of coal. Digging out a lot of space near lava or bedrock will help you to find all the ore you can.
Dirt is also non-renewable, though there is simply so very much of it that this is unlikely to be a concern. The same goes for sand, which is found copiously in deserts and beaches, as well as all over the place underwater.
Sandstone is non-renewable, which is a shame, as the pale yellow stone is very nice for buildings with particular appearances.
Renewable resources are more frequent, and usually less valuable.... usually.
Wood and leaves are renewable, as are all foods- the sources of all of these can be grown or bred on your own land in your own space as long as you have the patience to keep doing it.
Interestingly, water and lava are both renewable in the same manner. If you create a 2x2 pit one block deep and place a bucketful of water or lava in one corner and another of the same resource in the opposite corner, you have just created an infinite source of whichever flowing resource you just put into the tub- so long as you wait a moment after collecting each bucketful.
Because of this, stone is also infinitely renewable, though only in the form of cobblestone. This means that smooth stone is not infinitely renewable, since it depends on coal for you to make it from cobble. This is because when a flow of lava and a flow of water encounter each other with neither flow being a source of water or lava, the spaces in which they meet will be filled with cobblestone. There are therefore easy ways to create ‘infinite cobble machines’, though these are usually fairly slow.
Also, because the tubs of water and lava produce infinite source water and source lava, you can use them to create infinite obsidian. A bit slowly, but still possible.
This means that in the end, if you’re not careful, you’ll find yourself doing all your work with stone tools- which are still usable, but simply not as good as iron tools nor as flat out effective as diamond tools. This also means that the only infinitely replaceable armor is leather armor- so be careful with your fancy diamond armor!
Also, you will need to meter out your use of resources. Don’t immediately spend all the iron you get, nor all the diamond you get, as soon as you get it. The only thing you absolutely must have diamond tools for is gathering obsidian blocks, so don’t spend all your diamonds until you are sure you have as much obsidian as you need to reach your eventual goal.
On the other hand, this does mean that you can build as much as you want with the renewable resources without any worry over whether or not you will run out....
...as long as you remember to actually renew those resources.