Mercedes boss Toto Wolff says the opportunities and risks presented by the 2017 regulations mean his team has no way of knowing whether it will continue to dominate for another year or fall behind its rivals.
Mercedes has won 51 of the last 59 grands prix over the last three seasons, taking three drivers' titles and three constructors' championships since 2014. Its recent domination was one of the main reasons its rivals pushed so hard for a regulation change this year, and Wolff admits he has no way of knowing whether his team has done enough over the winter to hold on to its advantage.
"When there is a regulation change it gives opportunities and risks, and we have set aggressive targets of where we think the car should be going, and also the engine, and we have been flat-out to achieve those targets," he told the team's website. "But will those targets be enough or will other teams come out of the blocks better than we do? We don't know.
"Whether there is a regulation change or not, it's always the time of the year when we are all very sceptical and question ourselves whether we have done a good enough job. This is very much the mentality within the team. It doesn't make our days more happy but it's how we function."
Wolff said several big decisions had to be made over the winter, not least the appointment of Valtteri Bottas as Nico Rosberg's replacement and the restructuring of the technical department following the departure of Paddy Lowe.
"There are many decisions that need to be taken. Many assessments to be made: the driver question was a difficult one, Paddy going was another, and to make the team stronger going into the future you need to carefully evaluate which steps you're taking, and this is why every day is important."