"I've had clients come in with long-standing eye infections and permanent lash damage due to incorrect lash application or low-quality products," she said.
"I refused to serve a client whose lashes were so damaged she would permanently lose them if she continued to get lash extensions. She told me she would get them done somewhere else," Diehl said.
Having studied beauty therapy at EIT and then trained in lashes at two different institutes, Diehl thinks it is important to understand the products you are working with and what lashes to use for each client.
"All clients have different medical backgrounds, eye-shapes, and requirements. I see a lot of people wanting a super glam look but what works for one person isn't going to always work for another," she said.
"People think it's easy to do but you're using chemicals and adhesives which can burn the skin around the eyes," Diehl said.
She warns against going to any person you may see advertising cheap lash extensions.
"Anyone can buy cheap products online and set up in their backyard, Hawke's Bay is really bad for it," she said.
Morris recommends asking a potential beauty therapist to see their qualifications and ask if they are a member of the New Zealand Association of Registered Beauty Professionals.
"One can expect to pay up to $100 for their first set of eyelash extensions and $70 for infills, I would beware of places which seem too cheap" said Paula.
Cheaper places may use what is called a cluster of eyelashes where instead of gluing an individual lash to each natural lash, a cluster is glued on one lash. This is often too heavy for the natural lashes and can cause lash breakage and damage.
The NZ association of registered beauty professionals has a directory on their website to find professionals.