Generally your extensions should last well over a week and start to thin about 2-2.5 weeks, become apparently a bit patchy by week 3 due to an average natural lash fall cycle.....Of course this is dependant on your personal lash cycle but on average this is what I commonly see. This is why 3 week fills is a thing! -You didn't clean your face/lashes/makeup/skin properly before coming. I can usually tell and will use another solution free of charge for a lash bath but it will eat up application time. Make up wipes contain oil & will not get make up from the base of the lid line and risk ripping out your natural lashes from the root = BAD. Cleanse kits are given free to all new clients but Foaming cleanser is highly recommended for ongoing maintenance! (daily cleansing) -Excess sebum. This is the oil the skin produces in the lash bed naturally. It occurs more in everyone naturally and can build up in the lash bed working against your retention. Especially in the summer months when our bodies sweat more. -Working out/sweating often and not cleaning properly. Sweat causes make- up to build up on your lid line. All your moisturisers, sunscreen and old hairspray, make up all sweats into the lid line eventually & builds up. then dust, old skin and fibres stick to it...great group for decoded or bacteria to grow: grossss! -Wearing regular daily foundation and eyeliner and not cleaning properly. Over time this builds up in the lash bed especially if its hot and sweaty weather and if left uncleaned properly, will create mess that will effect retention. Even the eyeliner you put on the lower lid makes its way to to the top lid with each blink and sits until cleaned our properly with a special lash cleansing brush. -Blasting your peepers under the shower or waterfalls. This will not help retention. - Saunas & steam rooms or heated rooms of the like for Bikram & Hot Yoga will reduce the longevity of your extensions. by at least half, heads up! Finally, some medications and medical conditions will cause poor retention of both the natural lash and lash extensions or cause poor natural lash growth/weak follicles and extensions just won't still long or lashes will literally fall out. Under no circumstances will I ever recommend to avoid using sunscreen. Melanoma is far worse than lash fall! I take great pride in ensuring the best retention possible on all clients! new Glue is opened every 28 days without fail!