Sew in hair extensions?

i hate my natural hair as its short and DONT want clip in extensions cause find them annoying and cant be botherd with clipping them in and out every 5 mins and dont want glue in so was thinking about sew in?? are tese really damaging as i dont want somethin thats going to proper reck my hair and was wondering if these are ok as i have heard very mixed response on them? also how long can you have them in for? i really wnat long hair withough clip in or major damaging my hair plase help!!