Building a compost bin is as easy or as complicated as you would like to make it.
In fact the simplest bin is none at all.
Just pile up organic matter and let it rot.
If if sits for a couple of years it should be finished compost.
A compost bin is just a means of making measuring a finished pile easier and keeping things neat and tidy.
It also makes it easier to keep out vermin and in certain area this is almost a necessity.
Town bylaws or property covenantsmay also make it mandatory to use a bin for the neatness and appearance of the community.
Some consideration needs to be given, however to the nature and number of the bin.
In order to work well a hot compost pile should be three feet high, three feet wide and three feet or more long.
Since this works well for a cold pile as well, it makes sense to start here.
Also when building a compost bin it is good to remember that one pile is seldom enough.
It may take time to accumulate the material for a full pile so one bin is used for this.
Another accepts the turned pile and a third holds finished compost until it can be used.
In actual practice for a cold pile one bin gathers material until full and then holds it as the pile matures.
I would advise turning it into a second bin before starting the aging process as it mixes the material at that time and speeds composting considerably.
This means the second bin hold aging compost and the first is free to accumulate more material.
In many areas it may take three years to break down the compost so a third bin is good to have for a three year rotation.
A hot pile builds in the first bin.
As soon as enough material accumulates it is turned into the second bin.
Three days later it goes from bin to three and three days later back again.
When it is finished the pile is used as soon as possible or certainly before enough material gathers in bin one to need to start the turning process once more.
So when considering building a compost bin, think of the number three and it starts to come together.