I've tried almost every 'home remedy' diy lash serum and a couple of store bought lash serums. When I ran out of my fLash serum around the middle of june I decided to try this. It is a little pricier than fLash, but I feel like it gave more obvious results. A super important thing for me was that this didn't irritate my eyes or the skin around them. I've had sensitivity reactions to eyecreams so I'm always wary but luckily this was all fine with me.
The brush is a thin long brush that makes application a breeze. I like to work my way through the roots of my lashes rather than applying it like eyeliner, as this way it seems to absorb better. I definitely noticed more growth and thicker lashes, especially when I curled them. I religiously applied this night and day after washing my face, and refrained from rubbing my eyes as much as possible.
I ran out a couple weeks ago and my lashes still look pretty good, so in between each 'course' you could probably have a rest period of a couple weeks before your lashes go back to normal again.