Lash extensions are applied to your individual natural lashes, so how long they last is tied closely to your own lash growth cycle rather than a fixed expiry date.
The Natural Lash Cycle
Natural eyelashes grow, rest, and shed in cycles, with each lash typically staying in place for around six to eight weeks before it falls out on its own, whether or not an extension is attached. Because of this natural shedding, extensions gradually thin out over time even with perfect application and aftercare, simply because the natural lash underneath them has completed its cycle.
How Long Extensions Last Before A Fill
Most clients start to notice visible gaps or thinning around two to three weeks after application, which is why a fill, rather than a full new set, is generally recommended on that schedule to keep the set looking consistently full. Leaving longer than three to four weeks between fills usually means enough natural shedding has occurred that a full new set is a better use of time than a fill.
What Affects How Long They Last
Aftercare has a real effect on longevity. Oil based cleansers and makeup removers can break down the adhesive bond faster, as can regularly rubbing or sleeping face down on the lashes. Keeping lashes clean with an oil free cleanser, brushing them gently, and avoiding waterproof mascara over the extensions all help the set last closer to the top end of the two to four week range.
Extensions And Time Away, Including Holidays
If you are travelling or going on holiday, it is worth timing your appointment so a fill falls just before you leave rather than partway through the trip, since humidity, swimming, and sun exposure can all affect adhesive bond strength. A fresh fill right before travel generally holds up better than a set that is already a few weeks old.
Getting The Most Out Of A Set
Booking fills on a consistent two to three week schedule, rather than waiting until a set looks visibly patchy, keeps the overall look fuller for longer and puts less strain on the natural lashes underneath compared to letting a set grow out fully before returning.