The lazy investor’s guide to getting stuff done

For many investors, every day is like that.

You’re probably sitting on some stock or fund you bought years or decades ago, which you know you should ditch but can’t be bothered even to think about. That isn’t the same as willful blindness, where you’ll defend an investment no matter what and attack anyone who suggests it might be wrong. This is more like benign neglect, where you know you’re wrong but don’t feel like doing anything about it.

It only seems benign, however. Sticking to the status quo is a great idea if your investment portfolio is perfect. Your portfolio isn’t perfect, though, is it?

Mine certainly isn’t.

In my Individual Retirement Account, I own a couple of mutual funds that charge way too much and earn way too little. How long have I meant to dump them and switch into cheaper, better-performing index funds?

About 10—15—no, make that at least 20 years.

My inertia has cost me many hundreds, probably thousands, of dollars I could easily have earned by moving to funds with higher returns.

Yet every time I think about switching, I seem to find something more urgent to do. My bookshelves need rearranging! Time to turn the compost pile! My toenails need a trim!

“Humans are short-term focused, so the present looms very large to us," says Cynthia Cryder, a psychology professor at Washington University in St. Louis. “The future feels less vivid and important, so it’s hard for us to prioritize our future selves."

At least I didn’t invest in the now-defunct Steadman mutual funds. In the 1990s, after decades of dismal returns, many Steadman investors no longer even remembered they owned them—inspiring the nickname “the Deadman Funds."

In one study of retirement savers, 68 out of every 100 said they weren’t saving enough, 24 of the 68 said they planned to increase their contributions to their 401(k) in the next few months, but only three of them did.

The more uncertain your environment feels, the stronger this “status-quo bias" will be. If a rising stock market appears to falter, your resolve to make changes will crumble.

How can you overcome your inertia?

Break it up. In the late 1980s, the New York Yankees sent star outfielder Rickey Henderson a six-figure signing bonus. Months later, the team’s auditors noticed the check hadn’t been cashed. A Yankees executive called Mr. Henderson to ask whether he’d had any problem cashing it. “No problem," said Mr. Henderson. “I’m just waiting for the money-market rates to go up."

A big sum of money rivets your attention and can fill you with fear of doing the wrong thing—making delay feel perfectly reasonable, even if you aren’t as zany as Rickey.

So parcel out big decisions into smaller pieces. Put money to work in equal increments over time—say, 1/12th of the original amount each month. That should minimize the regret you might feel from investing either too much at the wrong time or too little at the right time.

Make a public commitment. It’s easier to make a change if you pledge to do it in front of other people. As for me, I hereby declare that I’m going to get rid of those vestigial IRA funds by New Year’s Day.

You probably can’t make your commitment public in The Wall Street Journal, but you can make a similar pledge to your family or friends.

Better yet, suggests Prof. Cryder, make a group with a few people you’re close to and commit to cleaning up your portfolios together. That will make each of you accountable to all the others and turn an unappealing chore into a social activity—much the way having exercise buddies not only gets you into the gym more often but makes it more pleasant.

Get a fresh start. A recent experiment with more than 6,000 university employees found that when invited to join their retirement plan in the future, they were significantly more likely to agree—and, later, to increase how much they saved—if they were prompted to begin investing after their next birthday or the first day of spring.

Certain dates such as birthdays and the first day of a new season seem to create “a dissociation in how we think of ourselves in time," says Katy Milkman, a behavioral scientist at the University of Pennsylvania’s Wharton School and author of the new book “How to Change: The Science of Getting from Where You Are to Where You Want to Be."

She and her colleagues call this phenomenon “the fresh-start effect." Such landmark dates, says Prof. Milkman, “separate us from ‘the old me’ and our past failures, helping motivate us to pursue our goals with new vigor."

So, if you’ve been meaning to pay down your credit-card debt, raise your 401(k) contribution, sell a losing investment or pay down your mortgage, commit to doing it immediately after your next birthday or the first day of spring. Set multiple reminders on your calendar.

You can go back to your cool drink now.