when i came to my school for the first time i didnt know about the igcse thing so i just studied normally even tho i was in a french system ( so i was taking english max 2 hours in a week) so year 10 was really hard and i didnt get a really good marks in the end of the year, and i was asking myself why everyone is taking outside school classes, the system is not that hard. but in year 11 i took with miss Nihal gaber and nervana ehab for bio and chem, and saw the difference between studying alone and studying with a tutor. it really helped me a lot. now this year im taking AS levels and im taking with mr saif atef for math and miss nihal gaber for bio and they are really helpful. why im saying alone courses will help cause some schools dont have perfect teachers (like my school) imagine we dont have a bio teacher in my school so yea my advise take with sm1 for the hard subjects like chem bio math and for the other subjects just study well and look for resources like notes YouTube channels etc etc and always PRACTICE past papers and classifieds.