Webber left Red Bull at the end of last season and moved to Porsche to join their World Endurance Championship programme.
The 37-year-old says the move came at just the right time, although he had considered leaving F1 12 months previously.
"The switch for me from Formula One was perfect timing," he is quoted as saying on crash.net.
"I felt that I was getting towards the end of my career in Formula One, which was in my hands.
"I was very close at the end of 2012 but I thought I'd do another season in 2013, which didn't go too badly, but the Porsche return was something I had a very strong eye on.
"You know I want to keep having success in car racing and Porsche give me this opportunity but also to grow with the brand in the future and achieve some really cool things, so there was a natural fit, and it worked out well.
"Formula One has been my life since I left Australia in 1995. I raced single seaters all that time, with a few years in sports cars in the 90s, but generally Formula One has been what I think of first when I wake up.
"So the mentality doesn't change too much, just your interest in that category isn't what it once was.
"I used to think about it all the time, while at the end of your career you don't; you start thinking about other things and your motivation isn't what it once was at that level.
"So you need a fresh programme, an exciting programme, something you can get your teeth into, which I can do with Porsche."