Saving is for access
Cash savings are suited to emergencies, near-term goals, and expenses where a market drop would make the timing painful. Interest, safety, and access may matter more than maximum growth.
Investing is for time
Investing puts money into assets that can rise and fall. A longer horizon may give the money more time to recover from declines, but no investment is guaranteed and past performance is not a promise.
Give each dollar one horizon
Do not make a five-year tuition bill depend on a portfolio built for retirement. Name the goal, choose the account and mix that fit, and revisit the plan when the timeline changes.