The difference between will and shall is now strictly adhered to by precise speakers.
Shall is becoming less and less common, especially in second and third person pronouns.
However, for the first-person pronoun, shall is still used to denote the simple future
Nowadays, english speakers in conversation use it in short form – ‘ll.
We’ll buy a new car.
I think I’ll go home.
By grammatical rules, in these sentences one has to use shall.
Some research has shown that most people consider ’ll to be a contraction of will.
And this research results proves that in actual usage will has been replacing shall.
People nowadays, use other verbs and forms of expression instead of using shall with second and third person pronouns to express a treat, promise, determination or command.