Washing too frequently tends to lead to dry skin. Showering rather than bathing, and keeping the showers short, will reduce the leaching out of the “natural moisturizing factor”, a mix of compounds that helps to protect the skin’s outer layer. Overly hot water also has a drying effect, so warm or tepid water is preferable.
You could use a flannel or sponge, but when you are trying to preserve skin-barrier function, the best thing is skin-on-skin – so nothing rougher than fingertips. Stay away from overly fragranced products, which can cause allergic reactions. The problem with soap is that it alters the skin’s pH and disturbs its acid mantle – the barrier that protect us against harmful bacteria and viruses, and also encourages healthy bacteria to live on the skin. You can buy cleansing bars, shower gels or body washes, but opt for soap-free, non-foaming, fragrance-free ones.
For areas that have oil and sweat glands, such as your underarms and private parts, it is good practice to wash daily. The problems come if you shower morning and night and maybe shower at the gym as well. If you are washing three times a day, it will be a struggle to maintain skin hydration.
After washing, pat skin dry. Avoid vigorous toweling as that can also damage the skin’s barrier.