Ideally all the biomass taken out of the soil is put back in, including essential nutrients. The most cost-effective and sustainable way to do this is to have compost areas. At the most basic it could be an off-the-shelf plastic bin, but eventually more are likely to be required.
There are many books or articles on composting, but I find there are two key issues that do not receive as much attention as they should: Rodent proofing, and location. By rodents, I am referring to unwanted guests that tunnel into your compost to make a cosy nest and then seek out and eat your composting worms. This is less of an issue with leaf-litter composting, but more so with kitchen waste (note: do not add cooked food or meats). This can be dealt with using suitable barriers. As for location, gardens are seldom planned around having 2 composting areas, and also associated set-ups for storing and creating leaf-litter compost. As a result, most of this potential goodness ends up being collected and trucked away instead of feeding your garden.
Like a well-designed kitchen, gardens need to accomodate the nuts and bolts of functionality. Aim for two well-sited composting units that are easy to fill from the kitchen – one for new material, the other for ageing material – and both easy to turn and aerate when required. Construction may for example be of cedar slats but with an inner fine mesh for rodent-proofing. In another area hidden away, have an area to store leaf litter – shred this with a lawn mower first if you can – and again use perhaps two or more wire enclosures to hold the leaf-litter in place.
Your garden may be too small to allow all of this, and so practical considerations come into play, but our aim should still be to feed the garden soil with well-composted organic material from our own kitchen and garden, if possible. And who can beat the wholesome smell of leaf-litter steaming after a summer shower, the feel of a good free-draining but moisture-retentive soil, and satisfaction that comes from doing it yourself in a sustainable way? Practically free too.