The only method I can say for certain that do NOT harm your hair from personal experience are the hairlocs method of extensions. It's not glue, braiding, weaving, and requires no heat etc... It's copper bands (like microlocks). I did a ton of research and saw the woman who did my extensions do a removal and the woman's hair was fabulous. She was putting them back in but switching colors. She had added highlights. If you get the right extensions it will not damage your hair or pul it out. If you use GOOD hair then it won't tangle. Mine never does but I also have European hair as opposed to the Indian hair which is thicker and more coarse. Not sure if that tangles. One thing I do is sleep with it in a pony tail and I wake up with fab hair. Run a brush through it and it's nothing! None have slipped or fallen out! But like I said earlier YOU GET WHAT YOU PAY FOR! If you are going to do it then do it right the first time!