Dermatologists are divided on this one. Some say yes, because it can remove deep-seated grime and residue which can lead to blocked pores and acne. But others say that because toners can be drying, only those who have really oily skin should use them.
The most sensible approach is this. If you work outdoors (exposed to elements and dirt) or wear a lot of makeup or have oily skin, use a toner. If you have dry skin and rarely have breakouts, then your cleanser’s already doing a decent job. Skip the toner and just wash face thoroughly.
But whether you use a toner or not, always moisturize. Cleansers and toners strip the skin of its natural oils. Also use a product that’s suited to your skin type.