How much must I practise?
This depends a lot on what you want to achieve and how many puzzles you want to practise, if you only practise 3×3 and just want to be sub-20 you can do with about 30 minutes a day. If you reached a certain level it doesn’t take that much practise on that puzzle to remain your speed as long as you also practise other puzzles. For instance: I barely ever solve megaminx anymore, but because of my regular other practise time I will probably not be much slower on it than one year ago.
