Go back to his first cap in 2001 and Simon was the raw youngster coming through the ranks and it was much the same at Spurs.
Turn the clock forward four years and, following a few retirements, he's now one of the more experienced internationals as new boss John Toshack starts to rebuild. Again, with approaching 150 appearances to his name at Spurs, he's now one of the more experienced players in a young squad at the Lane.
"I first got called up against Qatar in 2000 and made my debut against Ukraine in 2001," he reflected. "If you look at it there are the likes of Ryan Giggs, John Hartson who are most experienced now, Craig Bellamy and Danny Gabbidon with the same amount of caps as me and we're just about the only players now with more than 10 or 15 caps.
"It's a bit like Tottenham really. Things change so quickly and it's like starting all over again for me with Wales as well."
Although Simon is determined to win both back-to-back World Cup qualifiers against Austria, he realises it's time to rebuild again for Wales.
"It's a difficult one," he added. "The squad we had two years ago was the best for a long time.
"That was a good team and we had some great nights and came so close to making the finals of a major tournament for the first time since 1958.
"It's all about rebuilding now. We haven't the biggest pool of players to pick from so players have to come in and gain experience.
"It won't happen overnight and I think the manager has said realistically the 2008 European Championships is what we're aiming at.
"I feel positive after the last international where we had to make a lot of changes, played a young side and got a great result against Hungary. Everyone who came into the squad did well, it was a good start for the manager and that was ideal.
"Everyone realises we're rebuilding but these are big games and you want to get good results to keep the confidence high."
Simon Davies is seeing a change in his standing as a Welsh international - mirroring his career at Spurs.