How much money will you be able to enjoy if you put $/€/£ 10,000 into your savings account, leave it for 7 years, and come back to it in 2022?
You might be twice as rich and look at a nice $/€/£ 20,000 without ever having done any extra work or without any additional money added to the original stash.
But you might also only look at $/€/£ 700 extra, just enough money to pay for a week’s holiday in a holiday resort. Not bad either, but certainly not good enough considering you spared the money for a whole 7 years.