Eyelash Extensions are placed in length (structural) layers. On average, the natural eyelash of a 20-50yr old woman is between an 8mm and a 10mm. Based on your desired outcome, Amplify artists can stay within 1-2mms of your natural lash length OR go 3mm+ for a glam effect. When you are designing your lashline in you mind's eye before you come in, decide on whether you'd like a medium style (some women don't want others to know their tricks but do want there to be questions about "what have they changed") or if you'd like to go longer. We always tell you your natural length when you come in for reference. Going even 2mm above your natural length is a huge addition (and my recommendation on your first visit). We appreciate and ask for photos of want you ultimately want, but just know one thing about pinterest or professional photos from online, most of those women are 13s, 14s and even 15s to get a good photo! At Amplify, we can run the range from 7mms-14mms (rarely do we use the 14mms unless you really want that GLAM level).
But did that really answer why layering matters.... um, not so much. I go off on tangents, Sorry.
Layering is the art of adding length, density and then style structure. After it is determined the look the client is going for, lash artists divide the lashline into ~5+ areas. In each of the areas, the lash artist will add the longest length lashes to give the length. After which, they will go back in at 1mm under the longest length chosen for each area and perform density lashing. Last layer, but not least, they will check each area to make sure that it is the right overall height/slope for the style that was selected by adding appropriate millimeters to each area.
Layering is a unique technique differing from something like doing lash by neighboring lash or doing a lash on the right eye and then one on the left, etc. All techniques require some sort of architectural plan, or they should. At Amplify, we layer and we are proud of it!