Are particleboard bookcases sturdy enough for a full library?

Across verified-purchase reviewers and community threads we read, MDF/particleboard cases like the Sauder and SUPERJARE units hold up fine for paperbacks and average loads, but readers stacking heavy hardcovers, manga omnibuses, or art books consistently recommend either reinforcing shelves, sticking to lower tiers for heavy items, or moving up to a metal-frame shelf. Specialist subreddit threads also warn that the printed backboard on cheaper cases can scuff or warp over time.