Both some and any are used to refer to an indefinite quantity or number. They are used when it is not easy or necessary to say exactly how much/many we are thinking of.
I need to buy some shirts. (The speaker doesn’t state how many shirts he intends to buy.)
Is there any milk left?
Difference between some and any
Some is common in affirmative clauses. Any is common in questions and negatives.
I want some rice. (NOT I want any rice.)
Have you got any rice? (More natural than ‘Have you got some rice?’)
Sorry, we haven’t got any rice. (NOT Sorry, we haven’t got some rice.)
Some in questions
Some can be used in questions when we expect or want to encourage people to answer ‘yes’. For example, some is common in offers and requests.
Would you like some more cheese? (The speaker is encouraging the listener to say ‘yes’)
Could I have some meat, please? (The speaker expects the listener to say ‘yes’.)
Have you got some razor blades that I could borrow?
Any in affirmative clauses
Any can be used in affirmative clauses after negative words such as never, hardly, without, little etc.
There is hardly any milk left.
There is little point in arguing any more.
You never give me any help.
Both some and any are common in if-clauses with similar meanings.
If you need any/some help, just give me a call.