The Finland international, 34, has three years left on his current Wanderers contract and is hopeful he can earn an extension after that.
"I'm not that old for a Premier League goalkeeper. When this contract finishes I'll be 37 and hopefully I will avoid big injuries so I can't see why I cannot play beyond this contract," he said.
"If you don't look after yourself you are not going to be a success on the field any more because you know others will look after themselves.
"You have to keep on top of your game and make sure you do the right recovery.
"I have never really thought about how long I could play on for but hopefully in the future I can take up coaching.
"With the experience I have I would be happy to help young goalkeepers come through."
Jaaskelainen's 12 years of service with the club is being marked by a testimonial season in aid of three local charities - Birtenshaw Hall, Paws for Kids and RDA Miller's Nook Riding School - and starts with a friendly against Hibernian at the Reebok on Saturday.
He is one of an increasingly small group of players who stay at one club for so long but Jaaskelainen said happiness played a big factor in that.
"The main thing is my wife and three boys have been very happy here," he said. "The football club has been a bit up and down but after a few seasons in the Championship we have built on our success in the Premier League."