The 35-year-old striker, who is Spain's record scorer with 59 goals from 98 appearances, was in prolific form for New York City in 2017, registering 22 times in MLS games, making him the league's top scorer.
But he admitted that seeing his teammate, Italian legend Andre Pirlo, retire at the end of this season, was a clear message that Major League Soccer is no easy league and that he must continue to work hard to maintain his level of play.
A solid MLS season earned Villa a call-up for Spain this past August, his first in three years. But an injury saw Spain coach Julen Lopetegui omit him from the squad one month later.
"[Seeing Pirlo retire showed me] that I have to train harder every day if I want to continue extending my career. Someday I will leave, as will everyone, it's a fact of life. But I'm going to fight to make it as late as possible," Villa told Marca.
After a career that included five seasons at Valencia, three with Barcelona and one with Atletico Madrid before leaving La Liga, Villa said he never felt he left Europe too soon.
"On the contrary, it was more than three years ago when I made the decision to come here and every day I am more convinced that it was the right decision."
Andhe defended the level of play in the United States, saying: "I think that anyone who has actually watched an MLS game can say that it's a very competitive, physical and attractive league."
He added that other players in Europe have inquired about potentially making the jump.
"Really, quite a few [have reached out]," he said. "The MLS is growing a lot and is having more and more global impact. Many have called me and are interested in what's going on here."
Regarding Spain's preparations for the World Cup next year, Villa was reluctant to compare them to previous squads.
"The quality of the national team is beyond doubt, but I don't think it's good to compare them to old teams. Each era is different and each team is different."
Does Villa need an MLS Cup to cement his legacy? - Via MLS
Despite David Villa's impressive numbers in MLS, does he need to lift MLS Cup to cement his legacy among the greats?