Books depends from person to person. Some people may understand from one book but another one can't. So it's not obvious for anyone to understand what others are saying.

Lets talk about physics. Physics is a conceptual subject . It needs both the Mathematics and problem solving skills to get a score . So to learn physics you should know the concepts very well. Now there are a number of books in markets which occurs to be the best for different people but it may not be perfect for you. So I will say that try to find out pdf's of different books on physics and try to understand the concepts from then. No need to read out of the syllabus just focus on the parts that are in syllabus and compare it with NCERT. if you see that it have enough information like NCERT as well as its easy for you to understand then you can surely buy that book. This is a way you can strategize to.

Now, chemistry is a informative subject. There is a lot of things to remember. So it would be better if you try to just give a read in one of the chapters present in NCERT and read that chapter from the pdf version of another book. Observe its understandable or not. If yes then judge that if the pdf contains all the information that are present in NCERT or not. If yes! Bingo! you got the book for chemistry.

The above process may sound boring but if you do this way you will get benefited because you will not be wasting times with books that are not so easy to understand as well as wasting money for the books from which you can't learn anything.

I hope this answer helps you. Have a great day!