Liquidity requirement

When calculating liquidity requirement, when do we need to add the cash inflows into consideration?

For example, John needs $30k for medication in the following year. John’s salary is $100k and he can save $80k. He will contribute all the $20k saving into the investment portfolio.

In calculating the liquidity need for the following year, do we consider just the $30?

Thank you

I would mention it. Often the CFAI leaves it out if salary and expenses equal, but i would always write that salary will be used for expenses and contribution to the portfolio.

In the end, you would end up with $20 inflow and $30 outflow, leading to $10 net outflow