There is one question that every physician investor has asked regarding their financial future, “How much money will I need in retirement?” Although advisors are very good at providing broad guidelines, the answer should always be individualized.

The 80% guideline. According to the Motley Fool, financial advisors project that a retiree will need about 80% of their working income to maintain a comfortable retirement. This projection assumes that a person’s outlay will decrease at the close of their working life. A retiree’s commuting costs will be eliminated, their wardrobe will be casual and less expensive, and there is a good chance that their mortgage will be paid off or downsized.

The 4% withdrawal. Another number often tossed around when figuring out your retirement savings goal is 4%. It is said that you should be able to take out 4% of your total retirement savings every year for 30 years. This formula assumes that you will steadily receive at least a 5% return per year on your retirement nest egg and that you will not make any annual withdrawals above the 4% mark.

Liabilities. Remember that some of your current liabilities may be eliminated by the time you retire. Chances are that medical school debt will be gone. Depending on the age of your children, you may have also completed paying for college. And any overhead regarding your medical practice including malpractice insurance will also no longer be necessary.

Including other sources. Don’t forget to include other retirement income sources when adding up your projection figures. Social Security will be a part of this as well as any pensions that you or your spouse will have access to.

What do want to do with your time? A huge factor to consider is what you plan to do during your retirement and how much it will cost. Will you go fishing twice a week? Play a round of golf every day? Travel to exotic destinations? See every show on Broadway? All of these pursuits have a price tag, and some price tags are larger than others. Keep these in mind when crunching the numbers.

Use a retirement calculator. Forbes compiled a very handy list of retirement calculators that include the Ultimate Retirement Calculator as well as the Vanguard Retirement Nest Egg Calculator. These two calculators as well as the others recommended by Forbes are free and offer an easy interface that will help you see where your savings needs to be to retire without worry.