Liverpool will have to spend money to keep winning trophies, according to Jose Enrique.
Jurgen Klopp's long-term vision at Liverpool finally began to take shape in 2018-19, as his side became Premier League title contenders and European Cup winners.
The Reds built on that platform to win the UEFA Super Cup and FIFA Club World Cup in the first half of the current campaign, while also moving above Manchester City in English football's pecking order.
City pipped Liverpool to the finishing post by a single point last season, but this time around there is a clear gap between the two sides.
Klopp's men are sitting 23 points clear in the top-flight standings with only nine fixtures left to play, and they will be crowned champions if City fail to win their game in hand at Chelsea on Thursday.
However, Enrique says Liverpool cannot afford to rest on their laurels once they secure a first title in 30 years, with an efficient recruitment strategy considered necessary for sustained success over a lengthy period.
"You have to keep spending," the former Reds defender told Sky Sports.
"It's very difficult bringing people in with this starting line-up, knowing that they are going to be a substitute from the start, but that is the key for Liverpool to keep winning things in the next few years.
"They need to strengthen the squad because when one of the starting line-up doesn't play, you feel the difference."
Enrique expects competition to be even fiercer in the Premier League next season after seeing Chelsea add Hakim Ziyech and Timo Werner to their ranks and Manchester United linked to a number of top players, including Jadon Sancho and Harry Kane.
A man who racked up 99 appearances for Liverpool between 2011 and 2016 added: "To win titles is very, very difficult but to win them every single year is even harder. More so in the Premier League. You can see with Chelsea, they've already spent so much money signing two players for next season, so they are going to try to be there.
"Manchester City already have an amazing team and Manchester United are probably going to sign some big players because they want to get up there again."