Some piano teachers in Singapore recommend that you take every practice session like the actual examinations, and go through in sequence every time. On the other hand, some piano teachers tell you that you should set aside for e.g. the weekends for intensive hours of practice.
However, what I recommend the best way to practise and master playing the piano is to actually practise daily, albeit for no more than 15 minutes each time.
Why do I recommend that you practise daily, and why only 15 minutes each time? I have reasons for each of that.
First of all, consistency is key when it comes to playing the piano. It is more important to practise consistently, and on a daily basis to get your muscle memory right rather than trying to cram in last minute. The best method to get muscle memory right is to practise consistently on a daily basis, rather than practising for 5 hours straight once or twice a week.
Second of all, why do I recommend only 15 minutes practice sessions? The reason for this has to do with human psychology. If you had to practise for 1 hour daily, you may not be able to do so on certain days because of your school/work e.t.c. If this happens often enough (which is likely possible), you will definitely break the habit of practising daily. That is bad. To prevent this from happening, you only want short piano practice sessions so you always have time for it daily, and also feel motivated to practise even on days where you do not feel like it, simply because it is so short and easy to get it over and done with.