I had blink and go and I had them quite a few times - at first I had them and fell in love with me new lashes. I didn't have to wear any eye make up at all and still looked amazing - right out of bed so as you can imagine that's pretty cool!
I kept having them re filled over the course of about 6 weeks I had them kind of permanently for that time.
On my 4 the set the beautition said my real lashes needed a break so she removed them and said I needed to wait 2 weeks before getting them again - I was gutted! And felt very bald and plain when they were off.
I did have some spaces but the remaining lashes were not any shorter.
Anyway my lashes grew back fully within 2 weeks but I didn't have them re done. Just upgraded my mascara (Lancôme Hypnose)
I do have them for holidays and by day 10 I start wiping baby oil over my lashes and they start to come away and I feel like that's more gentle than the professional method which stings like a MF!
When I had them applied I would ask for loads to be applied and then any that were lost did not cause spaces in the semi lashes. That made a real difference.
They do move around and even when showering and washing hair you cannot remove the water from your eyes like normal you just have to let it drain off which is a bit irritating but the steam really loosens the glue.
Sorry for long post! Hope it helps :)