Daniel Ricciardo thinks 2018 will make him "stronger" in the future.

That is despite the fact that he said this year was actually the "hardest" in his entire career.

"100 per cent yes," the Australian said.

Ricciardo had highs in 2018, but also lows amid technical trouble with his Red Bull, the strength of his teammate Max Verstappen, and his decision to switch to Renault for 2019.

"There was the contract stuff, the high of Monaco, the low of the DNFs -- mentally it's tested me," he said.

"But I feel it's only going to make me stronger down the track."

Many believe it was the ascension of Verstappen that made Ricciardo's 2018 so difficult, and prompted his decision to leave Red Bull.

"I think Max Verstappen is threatening to become the fastest all-round driver in formula one, and I think that's hit Ricciardo hard," Sky F1 commentator Martin Brundle said.

"To an extent, Max has had done to him what he did to Seb Vettel at Red Bull."

Ricciardo agrees with Brundle that 2018 knocked him around psychologically, and is therefore looking forward to his annual return home to Australia.

"I love home and I love the summer but I think this year more than any other year, it'll be so nice to get home and to switch off," he said.

"I don't think I'm going to tell any of my mates when I get home -- I think I want just three or four days with myself," said Ricciardo.