This depends largely on what type you choose and how much work needs to be done in order to install them. Clip-ins are usually the quickest option since they simply require clipping into place; this could take anything from 5 minutes up to an hour depending on their size. For sewn-ins or tape-ins it may take longer in order for the extension pieces to be properly attached – around 3 hours per session – but these offer a much more permanent solution that can last for several months. Clip-ins are considered by some to be the best hair extension option.