1. You are UNABLE to brush through your extensions - the lash extensions are applied poorly. You should be able to glide seamlessly through your lash extensions with a mascara wand. 2. Your eyelash extensions poke and irritate your eyes - the lash extensions are applied to your skin instead of on your natural lashes 1mm away from skin. 3. You lash extensions appear heavy, fake or too thick - a properly trained lash tech will be able to work with your lashes and eyeshape to create a set that flatter your look and a proper set of lashes should not make you feel a thing. What's worse is that heavy lash extensions will damage your natural lashes. 4. Your full set is completed within 1 hour. Industry standard of a TRUE full set application takes 1.5 - 2 hr.
I have been removing quite a few sets of poorly applied lashes for clients recently. Please be cautious of super-cheap extensions services. it could cause more damage and cost more to fix.