How often should I use this sulfur soap if I have oily skin and have never used sulfur before?

If sulfur is new to your routine, treat the first week as a test. Use the bar two or three times a week on the oily areas only, rather than every day all over the body. Sulfur can feel active on skin, and the product guidance is to start gently when you are not used to it.

After that first week, check how your skin reacts. If it feels comfortable and not tight or red, you can wash daily on the face, back or other oily zones. If the skin feels dry, reactive or dehydrated, cut back to every other day or twice a week and follow with a plain moisturizer.

What matters as much as frequency is what you pair with the soap. Strong exfoliating acids, retinoids and other drying products should not be combined with sulfur unless you already know the combination is tolerated. In case of irritation, burning or redness, stop using the soap and ask a specialist for advice.