I have 3 compost bins, one plastic one I bought, and this double one my hubby built out of old pallets.
The idea being - one we add to, one doing its thing, and one finished/almost finished to use on the garden.
Sometimes it doesn't always work that one is ready to use and I have two sitting there decomposing down.
My husband made it so the front boards slide out for easy access, and so I can add boards as needed. It is very easy to use, and I love it's made by recycled pallets that would of been thrown in the skip at his work. He also put a lid on it with hinges, to try keep our dogs and too much rain out!