A shikibuton does not carry moisture by itself — dampness depends on the environment and daily care. In humid southern conditions, pair it with a moisture pad, air and stand it regularly, and keep the underside dry. With this routine of moisture management and clean bedding, it lasts well over the long term.
If you are comparing Japanese futon care with a conventional mattress, focus on airflow, dryness, regular turning, and the right cover; these habits help the shikibuton keep its shape and comfort.