I have very straight, short lashes that grow straight down, so the immediate LVL results are very dramatic for me. Ive had it about 5 times in the last two years - I'd do it for a special occasion like a wedding or holiday, but the last wedding I went to I just couldn't be bothered and slapped on more mascara instead. It's probably good holiday where you'll be swimming etc.
The first time I had it done I was amazed, literally felt like I'd had a facelift.
One time my lashes did droop overnight, I managed to flick them back up again but they didn't look as good as other times. I think that was just bad luck or how I slept or something.
If you wear contacts you'll have to skip them for a day and wear your glasses. The treatment can sting a bit if you have sensitive eyes like me, but nothing unbearable.
You need to keep them dry for at least 24 hours, so no bathing/ sweating/ steamy environments. I tend to get mine done at an early appointment where I know I can have a slight lie-in the next day and just shower straight away. My eyes get crusty especially when I'm asleep, so I'm always desperate to wash my face by the time I wake up. They should give you a spoolie so you can brush them out regularly. At my last appointment she also gave me some serum.
The worst bit is when it starts to grow out so you have some super curly and some new straight lashes, but a bit of mascara usually gets them looking ok. For me, the best result doesn't last long enough for it to be a regular treatment, so I keep it for occasions only.