they do take some getting used to, but I had long nails before so it wasn`t that hard, I`m and Electronics design engineer and work with parts that need a magnifying glass quite often and I can still do it with nails, I think tiny screws and typing took the most to figure out though (about a week).
the sort i have are called Acrylics, and they`re almost bullet proof! LOL I accidentally slammed one in a drawer once, didn`t touch it! and no it doesn`t destroy the nail underneath, I still have mine intact, here:



this is the underside and you can see clearly my own nail in there, if I thought it would hurt my real nails I wouldn`t have it done, and yes, you do need to have infills every 3-4 weeks as the nail grows out. xx