Chelsea forward Raheem Sterling has said he "couldn't afford to waste time" by staying at Manchester City.
Since 2018-19, the 27-year-old made fewer league starts each season for City, with 23 last term.
After seven years at City, Sterling wanted a "fresh challenge" and made a £50m move to Chelsea last month.
"Since I was 17 I've been a regular starter, and to get to the peak in my career, not to be playing regularly was something I wouldn't accept," he said.
"My personality is to try to fight and change the scenario, but it didn't come and that was it.
"As a person you strive to achieve, and I just felt my time at City was getting limited on playing time for different reasons.
"I couldn't afford to waste that time, so I needed to keep that same level and a fresh challenge."
Sterling was signed by Liverpool from the QPR academy in 2010 and became a regular in 2012-13, before a £49m move to City in 2015.
Sterling won four Premier League titles with City, the League Cup five times and the FA Cup once, but the Champions League eluded them.
City lost 1-0 to Chelsea in the 2021 Champions League final, and although Sterling started that game, he only started five of City's past 13 knockout games.
"It does feel like coming home," he added. "I feel like it's my full journey - going up to Liverpool and manifesting what I wanted, going to City and living the dream, and now coming back to London as a grown adult.
"I've been in the football game a while now, I've got my head on my shoulders and I know exactly what I want from my life and football, so it's the perfect time to come back and have a new challenge."
Aiming to be 'more vocal and drive the team on'
Since his Premier League debut aged 17 with Liverpool, Sterling has made 469 first-team appearances and earned 77 England caps, and aims to be more of a leader at Chelsea than he was at City.
"Inside the changing room and at the football club, there's a developing side of me which I'd like to see a lot more," he said.
"That's to be more involved in decisions in the dressing room, to be more vocal, and try to drive the team on."
Sterling was Chelsea's first major signing since the Todd Boehly-led takeover, which followed the club reaching the final in four of the six cup competitions they played in over the past two seasons.
"This was the option that was tailor-made to my personal goals, and with my family as well, and the direction the club is going in," Sterling added.
"It's a team that's competing and only going to get better. With the new ownership as well, it made a lot of sense.
"It was tough, of course, with the time I spent at City and there's lots of memories and top moments.
"But the year and a bit that I was in and out of the team taught me a lot about myself, made me value a lot of things and I tried to get things in order.
"You have to make the decision that's best for yourself."