OTTAWA – While it may seem that the election campaign has begun, with parties exchanging partisan attacks and unveiling their ads, slogans, and in some cases campaign buses, it's not official yet.

If that is surprising to you, or if you weren’t aware that there even was an election on the horizon, here's what you need to know.

The federal election is scheduled for Oct. 21. By law, the campaign period before the vote has to be at least 36 days long, meaning that the campaign will have to be kicked off by this Sunday, Sept. 15 at the latest.

Could the kickoff happen earlier? Yes. It could happen any day now. It could have happened as early as Sept. 1. Though there a few days between now and the 15th that may be less than ideal timing. Sept. 10 is the Manitoba election, Sept. 11 is the 18th anniversary of the 9/11 terrorist attacks, Sept. 12 is the first national English leaders' debate organized by Maclean's/Citytv and, well, Sept. 13 is Friday the 13th.

So why hasn't it happened yet? That is largely a question for Prime Minister Justin Trudeau. It is his decision when to launch the country into campaign mode. But there are other factors at play that offer some insight into his decision-making process about the timing. The arguably two biggest factors this time around are money and current events.

Under new election rules, each national political party has a limit of approximately $28 million that it can spend during the campaign period, while individual candidates can spend on average $110,000. That amount stays the same whether the campaign is the minimum 36 days or the maximum 50 days, and totals approximately $65 million if a party runs a full slate of candidates.

There is also a limit on what can be spent in the pre-campaign period, which began at the end of June. The opposition parties have to respect that limit in their efforts to get their message out early. The Liberal Party also has that limit, but because it is in government, it has the advantage of still being able to crisscross the country and make announcements and spending re-announcements on the taxpayer dime. That will have to stop as soon as the election is called.

And then there's the question of how effective spending money on political messages is in the final weeks of summer.

Were you paying attention to political news over Labour Day weekend? The Liberals likely guessed not, and that's why the prime minister didn't head over to Rideau Hall to have the Governor General call the election while you were likely still rolling your way back from the cottage, or through a back-to-school supply aisle.

Then, with much of Atlantic Canada bracing for, and now recovering from Hurricane Dorian, parties have pared down their regional campaigning and it's likely the government will want to ensure all is stable before kicking off the campaign now.

What changes once the election is called? Once it is officially on, expect the battling for votes to ramp up, with party leaders offering daily policy announcements and attending rallies with supporters in every corner of the country.

There will be more attack ads as leaders attempt to frame themselves in contrast to their competitors, and likely more politically damaging stories to be surfaced about a leader, or a candidate.

You will likely see more political candidates and their teams at your doorsteps. As each party gets closer to, and fills its roster of candidates in each of the 338 ridings, they'll be hitting the streets to pitch their plan to their prospective constituents.

What's the difference between calling an election and a 'writ drop'? Nothing. The term "writ drop" has become the colloquial phrasing but, in fact, no one drops anything. The more accurate phrasing would be that the writs—one for each riding— are drawn up, and issued.

Writs are the official documents that allow what is called a "returning officer"— essentially the overseer of each riding's election—to conduct the election.

The writs are issued once the prime minister visits the Governor General to seek approval to dissolve Parliament. That process is the prime minister launching the campaign. Typically, he'll then emerge from Rideau Hall and explain why it is election time and take the first chance to frame what the vote will be about.