Toners, essences and serums are an integral part of an effective daily skincare routine, whether or not you're into the Korean 10-step skincare routine.
For those of us who don't have the luxury of time, amongst the three, try to not skip essences or serums before your moisturiser. Use at least 1! They are the ones which aid cell turnover and target skin concerns (regenerate, repair, firm, whiten and basically heal & provide us with the kind of effects we want for our skin). Your usual toner & moisturiser will not be sufficient if you want some changes to your current skin condition - they only maintain it.