For DIY investors, asset allocation ETFs may be the greatest gift to come along in decades. It’s never been easier or cheaper to build a globally diversified portfolio that needs almost no maintenance. But compared with a balanced mutual fund, even one-ETF portfolios have a few potential drawbacks.

First, at most brokerages you still need to pay a commission of up to $9.99 any time you buy or sell ETF shares. If you’re making smallish monthly contributions, that’s a major obstacle. It simply isn’t cost-efficient to trade unless you’re investing at least a couple of thousand dollars each time.

Moreover, mutual funds give you the opportunity to automate your purchases. With the money taken from your chequing account every month, your savings become more consistent, and soon you may not even notice them. Unfortunately, when you use ETFs, you don’t get that benefit.

Finally, mutual funds make it easy to reinvest all distributions (dividends and interest payments), which means there’s no cash sitting idly in your accounts.

Of course, index mutual funds have their own drawbacks. The Tangerine Investment Funds, for example, offer all the benefits mentioned above, but carry a fee of 1.07%, which is no longer competitive. The TD e-Series funds offer these three benefits at about one-third the cost of Tangerine, but you need four funds to build a globally diversified portfolio, and you need to rebalance these yourself from time to time.

You can argue that robo-advisors combine many of the benefits of mutual funds and ETFs. It’s easy to set up automatic contributions from your bank account, and any time dividends or new contributions land in the account, the cash is quickly reinvested in new ETF shares. And most robos don’t charge commissions for trades. Problem is, these services aren’t free: robo-advisors typically charge about 0.50% annually (less on large accounts), which is $250 a year on a modest $50,000 portfolio, and that’s in addition to the management fees on the ETFs themselves.

What if you were able to combine the useful features of a mutual fund or robo-advisor with the lower fees of an asset allocation ETF? If you’re willing to put in a little effort at the beginning, it turns out you can create a DIY portfolio with the ideal mix of low cost and hands-off convenience. Here’s how.

1. Choose a brokerage with zero commissions

While most online brokerages charge between $4.95 and $9.99 per trade, there are a few options for trading asset allocation ETFs with zero commissions. These brokerages are ideal for investors who are regularly adding small amounts of money to their portfolio.

•  Questrade offers all ETF purchases for free. (The normal commission of one cent per share—minimum $4.95, maximum $9.95—applies when selling ETFs.). While this presents an opportunity to build a portfolio of multiple funds, using an asset allocation ETF means you never need to rebalance, which has behavioural benefits even if you’re not paying commissions.

•  National Bank Direct Brokerage now offers commission-free trades on all ETFs, the only big-bank brokerage to do so.

•  Disnat (Desjardins Online Brokerage) also offers commission-free trades on all ETFs.

•  BMO InvestorLine has a menu of commission-free ETFs, including 14 asset allocation ETFs. The list includes the major one-fund portfolios from Vanguard (VCNS, VBAL, VGRO) and iShares (XCNS, XBAL, XGRO) as well as BMO’s own family (ZCON, ZBAL, ZGRO).

•  Scotia iTRADE lets you trade about 50 ETFs with no commissions. Unfortunately, the list is no longer on their website: you need to have an iTRADE account to access it. While most of these ETFs are not useful for traditional index portfolios, eligible funds include XBAL and XGRO.

•  Qtrade offers a selection of commission-free ETFs, and the list includes both XBAL and XGRO.

A note for investors who are starting from zero: some brokerages charge a quarterly $25 inactivity fee on small accounts. The minimum balance to avoid these charges is $1,000 at Questrade, $10,000 at Scotia iTRADE, and $25,000 at Qtrade. Read the fine print before you open your account.

2. Automate your deposits

In general, you can’t set up an automatic purchase plan for ETFs the way you can with mutual funds. But every brokerage allows to you set up regular deposits of new cash to your accounts. Even if that cash doesn’t get invested immediately, there’s value in automating your savings rather than relying on ad hoc contributions that can easily get forgotten—or spent.

Automating cash deposits is particularly easy if your online brokerage is associated with the bank where you hold your chequing account. But even if you’re using Questrade or Qtrade to take advantage of commission-free trades, you can arrange an automatic transfer of, say, $500 per month to your TFSA from your third-party chequing account. If you can’t find the forms on your brokerage’s website, call them and ask for instructions.

You’ll still need to log in to your investment account to make a trade and invest that cash. But if you forget from time to time, it won’t make much difference: you can just make a larger trade next month. The important thing is that you won’t neglect to save.

3. Set up a dividend reinvestment plan (DRIP)

Robo-advisors automatically reinvest the cash when ETFs pay dividends or interest, which allows you take full advantage of compounding. For small portfolios, this is a pretty minor benefit, especially if you’re able to reinvest that cash with commission-free trades. But, hey, every little bit helps.

If you’re using an asset allocation ETF in a self-directed account, you can get the same advantage by enrolling in a dividend reinvestment program (DRIP). All discount brokerages offer these plans, and you can usually enroll easily online. Unfortunately, not every ETF is eligible at every brokerage, so it’s worth a call to the customer service desk if you’re not sure whether your asset allocation ETF is on the list.

When you’re enrolled in a DRIP, you’ll receive your dividend and interest payments in the form of new ETF units rather than cash—with the caveat that only whole units can be purchased. For example, if the ETF is currently trading at $25 per unit and your holding pays a $127 dividend, you’ll receive five new units plus $2 in cash. (No commissions are ever charged on DRIPs.)

DRIPs are a great way to way to keep your investments compounding in a TFSA, RRSP or other tax-sheltered account. But I generally don’t recommend them in non-registered accounts, as they can complicate your recordkeeping. If you’re making a few commission-free trades every year anyway, it’s easier to just mop up the idle cash in your taxable account at that time.

The (minimal) effort is worth it

If you’ve put the above three steps in place, then you’ve ticked the important boxes for a solid investment plan: you’ve got a broadly diversified portfolio that requires no rebalancing, your annual fees are super-low, you’ve got a regular savings plan, and your transaction costs are close to zero.

The investment plan I’ve suggested here isn’t entirely hands-off compared with, say, the Tangerine Investment Funds or a robo-advisor. With those options, once you’ve opened your account and set up your regular contributions, you could safely lapse into a coma for a few years and your portfolio would likely be in great shape when you woke up. But you do pay a significant amount for that benefit.

I’ve long argued that paying a little more for convenience is well worth it: that’s the reason I recommend asset allocation ETFs rather than assembling a portfolio from three or four funds, which would have a lower MER. What I’ve outlined above, in my view, strikes the right balance: it’s not the absolute cheapest option, and it’s not the absolute easiest, but it scores very high in both categories. If you can muster the energy to log into your accounts a few times a year and make a single ETF trade each time, then you’ll be well on your way to long-term success as a DIY investor.