Should auld contestants be forgot, and never brought to mind?

A few Conservative leadership candidates might be asking themselves this question on New Year's Eve.

That's because the first deadline in the Conservative leadership race looms on Dec. 31, when contestants who have already launched their campaigns have to pay the party a $50,000 compliance deposit in order to stay in the running.

This is on top of the $25,000 registration fee that was due upon entry into the race. Another $25,000 has to be paid before Feb. 24 — and only when that second and final instalment of the registration fee is paid do candidates have access to the party's list of members.

Access to that list is vital for a campaign, as it makes it possible for contestants to contact every member eligible to cast a ballot for the next leader, so there is an incentive to get that second $25,000 in as soon as possible.

The compliance deposit is held as security, to ensure candidates meet all the requirements of the leadership campaign, and will be returned to them after the campaign is over. The registration fees are not refundable.

Though contestants are able to donate $25,000 to their own campaigns, they need to raise at least $75,000 from donors to make the compliance deposit and second instalment payment.

Chris Alexander, Maxime Bernier, Michael Chong, Kellie Leitch, Pierre Lemieux, Erin O'Toole, Lisa Raitt, Andrew Saxton and Andrew Scheer are fully paid up.

Rick Peterson has paid the compliance deposit, along with the initial $25,000 fee.

In an email to the CBC, Brad Trost's campaign says the Saskatchewan MP will be "complying to all the [Jan. 1] requirements."

Steven Blaney, Daniel Lindsay and Deepak Obhrai did not respond to inquiries from CBC News. According to quarterly financial reports, Obhrai raised only $1,100 in the third quarter of 2016.

Fourth quarter data won't be available until early next year, but several candidates launched fundraising blitzes to close this year. Scheer's campaign tweeted that it raised nearly $22,000 in a day on Dec. 19, while Raitt's campaign raised almost $44,000 in a 24-hour fundraising drive on Dec. 13.

Thank you! Let's keep going: <a href="https://t.co/TOcYyCzf8J">https://t.co/TOcYyCzf8J</a> <a href="https://twitter.com/hashtag/cdnpoli?src=hash">#cdnpoli</a> <a href="https://twitter.com/hashtag/cpcldr?src=hash">#cpcldr</a> <a href="https://t.co/0PRRfCMaVm">pic.twitter.com/0PRRfCMaVm</a> —@lraitt

Still time for Kevin O'Leary and other new entrants

The Dec. 31 deadline applies only to the contestants who have already thrown their hats in the ring. After that, new contestants can get into the race by paying the $25,000 registration fee and the $50,000 deposit immediately upon filing (along with the 300 signatures of party members from at least 30 ridings in at least seven provinces or territories).

This gives Kevin O'Leary and other potential entrants into the race until Feb. 24 to gather the necessary signatures and funds. On Friday, O'Leary announced he'd launched an exploratory committee — which includes Conservative MP Guy Lauzon and former Ontario Premier Mike Harris — to gauge his chances for a leadership bid.

If O'Leary officially enters the race, he might choose to do so after the Jan. 17 debate scheduled to take place in Quebec City, which will be held entirely in French.

O'Leary doesn't speak French.

Contestants who are already in the leadership campaign have a number of advantages over later entrants. They can tap donors twice to a limit of $1,525 a pop — once in 2016 and once in 2017.

The 14 participants in the Conservative leadership candidates' bilingual debate are seen in Moncton, N.B., on Tuesday, Dec. 6, 2016. (Andrew Vaughan/Canadian Press)

Earlier entrants also had an incentive to sign up members. Before Oct. 28, the party paid candidates $5 for each member he or she signed up. After Feb. 28, however, contestants will be charged $5 for every new member they sign up. But it might be worth the cost: keeping new members' names off the list until later in the race prevents other candidates from having access to their contact information.

The winner will be announced on May 27.