Guardiola, who took over the reins of his boyhood club in summer 2008, prefers short-term deals and signed a one-year contract extension in February to keep him at the Nou Camp until the end of next season.
The 40-year-old told Italian television channel Rai Sport: "I think my time is ending here in Barcelona.
"I'm fine here, but when you're at a club like this you cannot stay for too long.
"Next year will be the fourth consecutive season as coach of Barcelona.
"Such a club must have a lot of courage to take a coach for so long, because the players get tired of coaches and vice-versa."
Asked if he might one day coach in Italy, the former Brescia and Roma midfielder added: "I'll come if I still want to coach. It takes enthusiasm and more to make such a decision."
Since taking over at Barca, Guardiola has already won eight titles including an unprecedented treble of Primera Division, Champions League and Copa del Rey in his first campaign.
The Catalan club are currently five points clear at the top of La Liga, through to the final of the Copa del Rey and in the quarter-finals of the Champions League.