Felipe Massa says his form in 2016 will be a key factor in whether he decides to continue in Formula One.
Massa is currently in his 13th season in F1 and has been confirmed at Williams for next season. The Brazilian driver has scored two podiums this year but is nine points behind Williams team-mate Valtteri Bottas in the championship.
Massa is keen to continue as long as he feels competitive with Williams.
"Next year will be the last of my contract, so I think that will be the most important season to understand if I continue or not," he told UOL Esporte."If I have the chance to be with a competitive team, I will [continue]. Otherwise, I stop.
"I'll be in F1 if I have a team like Williams, with whom I am very happy and they are also happy to have me. When you love working and feel loved, that is what gives [you] motivation to continue."
Massa is one of four drivers on the grid to have exceeded 200 race starts -- Jenson Button, Fernando Alonso and Kimi Raikkonen are the others -- and does not think he will struggle to make the decision to retire when the time comes.
"I do not think I will be afraid to stop, I think I'll be fine; I know that everyone will have to stop at some point. But I do not think that time has come yet."