Having entered F1 as a Red Bull junior, the Australian is now an undisputed top driver and looking at a potential move to Ferrari or Mercedes.
But Red Bull wants an answer by the summer.
“The next contract I sign must be ‘the contract’,” Ricciardo told El Confidencial newspaper.
“I can’t say what I’ll be doing in five years, so that’s why this next one has to be perfect for me.”
Red Bull has warned that it can pull Carlos Sainz back from Renault to replace Ricciardo for 2019.
But Ricciardo insists: “I’m not in a hurry. The team wants to have it done by the summer, but if the team tells me we can wait until October, then I can wait.”
The 28-year-old is a happy and ever-smiling member of the F1 circus, but he disagrees with Red Bull’s recent assessment that he was 50 per cent to blame for the crash with Max Verstappen at Baku.
“For people who know this sport, they know it was not my fault,” Ricciardo insisted.