Em, I don't think you quite understand the nature of a Canadian winter. It's not if you need a boost. It's when. Batteries lose % of their capacity with every 10c drop. A battery with 50% capacity can freeze solid, requiring days indoors to thaw. Faster if you risk blowing it up and immerse (not submerge) it in a bathtub of warm water. And often it's useless afterwards anyhow. The freezing can damage the plates inside. The stock battery that comes in the car is good for perhaps 2 years.
Our aftermarket carries batteries better suited, tho. Some with electrolyte that won't freeze above -70c. I make a point of buying a battery twice the recommended size for my cars. My first Mitsubishi Mirage was running the battery recommended for a V8 pickup.
The booster packs are a good option, if it's big enough. Small ones simply burn themselves out trying. And engine locked up with motor oil the consistancy of treacle isn't gonna turn over for a handfull of AA rechargables. My booster has a pair of UPS gel cells rated at half my car battery's cap. And it goes into the house with me everynight to warm up. But often, the only thing that'll get a car turning fast enough is to hook up someone else's engine charge in circuit, let that force some charge into your own battery, and then crank with the combined capacity of both batteries, and his alt.
