The 34-year-old, who has scored 14 of Sunderland's 24 Premier League goals to date this season, put pen to paper on a three-and-a-half-year deal when he arrived on Wearside from Toronto in January 2015, and he signed a 12-month extension last summer.
But Defoe, who was courted briefly by former club West Ham last month, has yet to make any longer-term plans, much to his mum's consternation.
He said: "My mum keeps asking me: 'how long are you going to play for? When are you going to do your coaching badges?'
I don't know, to be honest
It's just like life, I take each day as it comes.
"Even my friends in football, Les Ferdinand and Ian Wright, I always say to them: 'do you miss it?'
They miss not just the training and the games, but just being around the lads in the changing room and stuff like that.
"I've always said that it's important that players try to play as long as they can
That's why I've always looked after myself, because I love it."
Defoe's exploits for the Black Cats earned him the North East Football Writers' Association player of the year award for 2016, which he received at a dinner in Durham on Sunday evening.
The event came days after touching photographs of his hospital visit to five-year-old Bradley Lowery, who is undergoing treatment for Neuroblastoma, were posted on social media by the youngster's grateful family.
Defoe said: "As soon as I walked into the room, he jumped up and grabbed me and said: 'get in the bed!' He got the covers on me, he said to his mum: 'could you turn the lights off?' He just wanted a cuddle and to go to sleep.
"You can imagine the unbelievable feeling
Obviously, it fills you with tears, but you can't show your emotions as he is only young and you don't want to show him you were upset.
"I have been blessed in life and it is a great feeling to be able to give something back and make someone so happy, a little boy who is having a tough time at the moment.
"Bradley is in my prayers every night
He is an amazing young man and I look forward to seeing him again."
Source : PA
Source: PA