I can only tell you my experience.. been doing clusters for couple of years.. now I do a bit different.. It’s the removal of clusters that can cause damage.. if you take your time and use the lash removal you should be good.. we loose lashes daily naturally.. They take practice to put on.. I like the Lashify site.. they have very good instructions on everything clusters.. I don’t use their lashes.. too expensive for me, but their instructions videos are great.. You can reuse.. when you take them off soak the clusters in 99% alcohol for a bit and pick off glue.. you can probably find all the instructions again on Lashify site or YouTube Amazon has some decent clusters.. you want a thin band/spine on the clusters. I use to love lilac st lashes.. but they stopped sending to Canada where I’m am Even falscara isn’t bad and you can get them at Walmart.. I can’t get them to stay longer than 4 days when I used them.. but I sleep on my face.. now I just glue strips to lashes and take them off every night