Smith, who signed on a season-long loan from Nottingham Forest on Tuesday morning, turned 31 in December.
For most outfield players, that would gradually mean turning their thoughts towards retirement.
But with the likes of Edwin van der Sar, Brad Friedel and Mark Schwarzer all plying their trade in the Premier League well into their 30s, and David James still going strong at Bristol City, despite having turned 40 last August, Smith insists there is still plenty of life in him yet.
"When you look at the goalkeepers playing in the Premier League, a lot of them are well into their 30s," he said. "People like van der Sar and Schwarzer who seem to have been around for ages.
"It just shows that goalkeepers are continuing much later in their career. I don't really think 30 or 31 is very old for a keeper any more."
So why are goalkeepers playing at the highest level much longer these days
"It's a combination of factors," Smith added. "The clubs look after their players much better now in terms of diet and nutrition.
"The physio team and medical department are looking after all players to make sure their career is prolonged, and with goalkeepers, the more experience you have, the better you are.
"You learn from each and every game you play, and good performances can carry you through to an older age than you could maybe play at as an outfield player."
Like most goalkeepers, Smith was a late developer anyway, making his professional debut for Brentford at the age of 22 after spells with non-league clubs Carshalton and Walton & Hersham.
He made more than 100 senior appearances for the Bees before joining Southampton for ?500,000, and like most young goalkeepers growing up in the 1990s, his hero was always Peter Schmeichel.
"When I was younger growing up, Schmeichel was always the goalkeeper I looked up to," he said. "Although it's hard to copy his technique and the way he played the game.
"He was a one off. I've seen his son (Kasper) play a few times and he's probably one of the few people who can get away with being like his dad.
"Schmeichel was always the main person I looked up to in terms of his international experience and the amount of games he played at the top level as well."
After a two-year spell at Southampton, Smith moved to Nottingham Forest in July 2006.
He made 141 appearances at the City Ground, helping Forest win promotion from League One to the Championship, but found himself frozen out after Billy Davies signed Lee Camp two years ago.
Camp, an England Under-21 international predicted to have an exceedingly bright future, has started all 36 of Forest's Championship matches this season.
As a result, when Boro came calling for Smith's services on Monday evening, he did not hesitate to answer the call.
"Lee has played very well this season and you can't argue with that," he said. "That's the reason why I haven't been playing - there's no other reason for it.
"It's difficult. Goalkeepers have got the goalkeeping union where you basically stick together.
"I think we're a different breed. We go out training on our own and keep together in this close-knit unity between the keepers.
"But it's difficult because there's only one position and only one goalkeeper that plays.
"It's difficult when you're working with the rest of the team week in, week out, but then not playing on a Saturday.
"It's hard, but there's a special bond between goalkeepers and I think that's universal throughout the leagues."
Source: Northern Echo
Source: Northern Echo