I book at least one or two flights each year using my Aeroplan points, and until now the way I decided whether I was getting a good deal was instinct.

I’d compare the cost of the same flight using points with the cash price, and then make a gut decision on the spot.

For example, 30,000 points and $140 dollars in fees for a one-way flight to Bogota last year seemed to be a better deal than roughly $500 in straight cash, so I went for it.

Of course, with the current Air Canada potential strike threatening to disrupt travel, now is a tricky time to try to book.

Nevertheless, earlier this week I looked at round-trip flights from Toronto to Edmonton. On the surface, it appeared to be a good deal: 22,000 points and $100 in fees.

When I searched up the same flight in cash, the cheapest option (which happened be the same Air Canada flight) was $260.

I’d be paying 22,000 only to save about $160. The deal didn’t seem so good anymore.

To get a more concrete answer of how to define a good deal, I reached out to Barry Choi, a credit-card and loyalty points expert at moneywehave.com and a regular Globe contributor.

After years of sifting through flight rewards on different platforms, Mr. Choi has a formula to find the “cost per point” (or CPP), which determines whether you’re getting a good deal on Aeroplan points.

He says you need to have a minimum cost per point of 1.5 to be getting a good deal on economy flights. For business class seats, you should have a cost per point of at least 2.

To calculate your CPP, you take the cash price of your flight, minus the taxes and fees you’d pay through Aeroplan, and divide it by the amount of points the flight costs, and multiple that number by 100.

For example my flight to Edmonton, in which I save $160 for 22,000 points has a cost per point of .81. He says it’s an atrocious deal, so my gut was right.

My flight to Bogota had a CPP of 1.2, so it was a better deal, but still not a great one.

Mr. Choi says you’ll often get the best bang for your points on flights that have less demand. That could include flights at undesirable hours or less popular routes. He added that Toronto to Vancouver seems to always have cheap flights available on points, despite being a popular route.

Flights that involve a codeshare with another affiliated airline also tend to have cheap rates.

Some of the best deals I’ve gotten in the past were between Toronto and Montreal, Toronto and Vancouver, and Vancouver between some Interior B.C. destinations.

Mr. Choi recently got a CPP of 1.9 on a one-way economy seat from London, U.K., to Toronto – one of the best deals he’s found as of late.

On other reward programs like RBC Avion, you should try to get a CPP of at least 1, although on certain promo flights he’s seen CPP’s of up to 2.33. Meanwhile, Mr. Choi says programs like WestJet have an exact cash value to their points, so CPP isn’t as relevant.

From now on, I’ll be calculating CPP every time I book a flight on Aeroplan. Do you have a system for when you use your travel rewards points? E-mail me at sfarooqui@globeandmail.com