And unlike painting the kid's room or mowing the lawn, our retirement account is closely connected to our future coziness in a life-altering way. So what's an inexperienced person to do?

Here are some of the most common mistakes non-pros make with their investments.

Risk

Have you ever made decisions that have gone badly? Then you may begin to understand the role of risk-taking in your life. How much risk are you comfortable taking? It's an important question.

When investing in the stock market, there are interconnected pieces that each have their own level of risk, separate from your personal risk comfort level.

Businesses experience cycles. Geopolitical episodes happen seemingly without warning. Disasters strike. All these and more can cause your investments to rise and fall. If you don't understand your risk, the risk of this investment instrument and that one, and understand your goals and objectives clearly, it may be very difficult to anticipate movement in your investments - much less know how you'd feel when faced with sudden changes in your portfolio.

Allocation

When you better understand risk and your tolerance for risk, along with your goals and time horizon, determining your allocation may seem more clear.

Once you know the level of risk you can tolerate, it is easier to determine your best allocation for your investments. How much volatility will each sector experience in inflationary conditions? What about the political risk of investing in overseas markets (and the potential returns due to those fluctuations)?

The goal in making a personalized allocation is to be properly diversified so that you feel more certain during market swings and avoid the feelings of wanting to stash your assets under the mattress instead of the market.

No plan

Then again, without a good plan it's hard to stay on any kind of track, since there is no clear roadmap for your future. Unfortunately, most do-it-yourself investors don't have a plan for their money future. Without a plan there is no path, and we are tempted to react - and possibly overreact - to every market fluctuation.

When you have a plan, you have a better chance of remembering why you are choosing this allocation and why you should make changes that reflect your rational thinking and not jump from one trend to another. Do you have a plan?

No input

Finally, but just as important as the previous points, do you have someone to talk to when you are a bit freaked by economic conditions? When things are making money, who needs a second opinion?

But when the market is suddenly down 1,000 points in a month, almost everyone is looking for answers and a direction. Emotions get in the way of any good plan we may have.

What can you do when you are concerned? Speak to a financial advisor or a friend to help you be more certain that you are making the most reasonable, sensible decisions.

You don't have to do this alone. You certainly can. And you may be really awesome at it. But if you are like most investors, you have many other things on your mind and could use a bit of help. Get it!