The best way to save money is to

a. wait to see if you have money left at the end of each month

b. begin saving only after you start making a lot of money

c. treat savings as a weekly or monthly expense

d. all of the above.

C. Treat savings as a weekly or monthly expense

This is not a mathematics question though it is the closest fit. Unfortunately, financial education and the importance os saving is not taught in school yet is among the most vital skills you must have to lead a comfortable existence.

C is the only answer.

Save 25% of what you take in after taxes and bills as early as you can and you will be a millionaire by 50.

Put that money money into a fixed annuity and you'll double in another 10 while collecting checks (not just Social security) but dividends on the annuity.

(25% is the average savings rate in Japan during the 1960 and 1970s.)

If you can consistently do 10%, you're still going to retire comfortably.

Just make it an absolute must in your budget.

If you have no budget, none of this really matters.