I'm am gonna recycle all my old soil this round too. It will be my first time doing this but I've read the soil gets better with age not worse so I'm in !
its really easy. after you use soil. dont let it dry out or you will have to re-apply with fungal and bacteria tea to wake them up again, as they go dormant when dry...
throw down some grokashi or bokashi to help speed things up... example... every 8-10in used soil, on top, a layer of grokashi. repeat process until container is full...
after couple months... just use, half used and half new as base, and then amend nutrients accordingly...
or you can compost it.... been throwing used soil in compost tumbler as a base with old bananas, strawberrys, oranges, potatoes, organic shit....