“I think 35 is the magic number that most people say if you've got to there, you've been lucky," Williams told the Robins Nest podcast.
“I'm here now, I'll be 36 in August.
“I don't know, I can't really answer that, but I feel good, though.
“Coming to Bristol City, I've felt as good as I've felt for the last few years, so I don't know.
“There's so many factors that go into it - there's family life also, being away from the children and your family home, just a lot of things that factor in.
“Whilst I can do that and there's a manager there that's happy with me and I don't feel like I can't do it anymore then I'll play.
“I can't really put a number on it, I always had 35 in my head, but now I'm at 35 I feel completely fine.
“I don't know, we'll have to see - I can't give you a number."