i have a large sal's fig in a full size trash can its about ten years old now, i hardly prune it ony for convienience. but it has roots at the service and i never changed the soil , i fertilize it but have never changes the soil i was wondering about sliding it out once it goes dormand taking some soil off the bottom and adding some new on the bottom and top. and maybe with my smaller ones i should follow this procedure every year afte it loss its leaves. any advice ?