At the recent Canadian Personal Finance Conference in Toronto, I participated in a panel discussion that touched on a wide range of investing topics. My co-panelists were Michael James and financial planner Jason Heath. and we were moderated by the esteemed Big Cajun Man. The first question we were asked to address is whether it makes sense to use an advisor or to invest on your own.

That was a tough question to tackle in a room full of committed do-it-yourselfers. It’s also one I’ve struggled to answer honestly in the last couple of years. I’ve been an advocate of DIY investing for some time, and I still believe many investors with uncomplicated situations are capable of managing a simple index fund portfolio on their own. Indeed, I think anyone with less than $100,000 or so should seriously consider doing so, because it’s awfully difficult to find an unbiased, fee-based advisor unless your portfolio is larger. And unfortunately, it’s all too easy to find a commission-based mutual fund salesperson who will turn your wealth into his own.

But over the years, as I’ve corresponded with readers—and more recently started working with clients —I’ve learned that DIY investing is much harder than it sounds. Experience has taught me do-it-yourself investors face a number of significant challenges—some technical, some behavioral. And unless they can overcome these obstacles, most would be better off working with a professional who provides unbiased advice for a reasonable fee. Here are the difficulties I see most often:

Analysis paralysis. I’ve spoken with investors who have accepted the theory of index investing for months, even years, but have never taken action. Ironically, those who have done the most research are most likely to be the deer in the headlights. They obsess over small details, or they can’t resist timing their entry point: they want to wait for the US market to cool off, or for interest rates to rise, or for some economic forecast to prove true. All the while they ignore the enormous opportunity cost of doing nothing.

And the longer they wait, the harder it is to pull the trigger. I have been surprised to learn just how many people are sitting on six-figure piles of uninvested cash. They know what they have to do, but they’re waiting for the right time to act. They don’t realize there is never a time when investing a lump sum feels good .

Focusing on products. Successful investing is about saving regularly, keeping costs low, diversifying broadly, and sticking to a plan. Yet it’s remarkable how many people believe the key to success is choosing the right products. That’s like thinking the most important ingredient in your fitness plan is the right pair of shorts.

For index investors, selecting appropriate ETFs is important, but whether it’s this one from Vanguard or that one from iShares is a trivial decision. Product selection is probably 10% of the process in terms of importance, yet it can occupy the majority of investors’ attention.

In our DIY service, we generally use the same ETFs for all our clients, and they’re the same ones recommended on this site. Even then, we could easily find substitutes for all of them and wouldn’t change anything meaningful. We earn our fee by helping people implement a disciplined savings strategy, helping them determine the appropriate amount of risk, ensuring their portfolios are tax-efficient and educating them about the importance of staying the course. Product selection barely enters into it, since it has little value.

Resisting simple solutions. Total-market ETFs have made it possible to hold thousands of stocks in dozens of countries using no more than two or three funds, and with annual fees under 0.20%. Toss in a single bond fund and you’ve got a richly diversified portfolio that’s super-cheap, easy to maintain, and likely to outperform at least 80% of professional money managers. But hardly anyone is content with that. Many DIY investors feel compelled to add unnecessary complexity and end up sabotaging themselves.

Advisors need to share part of the blame here. Far too many think they can add value by tossing sector funds, exotic asset classes, or individual securities into the mix, none of which is likely to boost performance. But they are often under pressure from clients who ask questions like, “What do I need you for if my portfolio is only four or five funds?” For many small registered accounts, a single balanced fund would probably be ideal, but you might be surprised at how many investors push back against simple solutions .

I’ll look at some other DIY challenges later in the week.