Williams test driver Susie Wolff suggests she may have to give up on Formula 1 after admitting it will be "very tough" for her to find a drive for next season.
The 32-year-old has been with Williams since 2012, going from development to test driver, but never getting the chance to race.
Although Wolff has been handed some Friday practice and testing chances, she says she cannot keep on waiting for a race seat.
Williams is set to retain Felipe Massa and Valtteri Bottas as its driver line-up for 2016.
"I can't wait on the sidelines forever for my chance," Wolff told CNN.
"There doesn't seem to be many opportunities for next year to get onto the grid. This is going to be a winter of reflection because either it happens or it doesn't."
She added: "I'm very ambitious but I'm also very realistic. It's going to be tough. It's going to be very tough."
Williams hired Adrian Sutil as its reserve driver earlier this year when Valtteri Bottas was forced to miss the season-opening Australian Grand Prix due to a back injury.
Sutil has yet to drive the Williams, and Wolff admits it was not easy for her when the team hired him as a reserve.
"My first thought was for Valtteri, who is a good friend, but being an egoistic racing driver my second thought was, 'OK, would I get the chance?'" she added.
"There was a lot spoken about it in the media. Adrian hasn't driven or tested the car so it was a lot of hot air about nothing in the end.
"At the time when Adrian was announced, of course it wasn't great for me. It just made me more determined to do a good job when I got in the car."