I generally know the location of my books. Very infrequently, it takes me more effort in locating but I find it within 15-30 min. I arranged them first by languages. For me, that would be Japanese and English. Then by methods or country. For example, all Greek, Hawaiian, German, Eastern European, Mexica, etc. I also keep all soups, salads, pastas, noodles, dumplings, desserts, breads, pizzas in their own area.