Signing global stars such as Lionel Messi, Cristiano Ronaldo, Gareth Bale and Sergio Ramos would not solve the problems at Manchester United, says former captain Wayne Rooney.
Rooney, who now plays for MLS team DC United, does not think Ole Gunnar Solskjaer's side will compete for the Premier League title next season.
"The first thing Ole has to do is build the squad and I don't think bringing in one or two players for £100m is going to help the players already there," said the former England skipper, 33.
Speaking to BBC Radio 5 Live's Sportsweek, he added: "Ole's better spending £30-40m on players with potential and building the squad around those five or six players.
"You could bring in players like Ronaldo, Messi, Ramos or Bale but it's going to cost you £350m and you'd get two years out of them and you've written that money off."
Barcelona forward Messi, 31, and Juventus attacker Ronaldo, 34, have won a combined 10 Ballons D'Or while Real Madrid captain Ramos, 33, has won the World Cup, European Championship and four Champions League titles.
Ramos' club-mate Bale, 29, has also lifted the European Cup four times - and has long been linked with a move to Old Trafford.
Rooney expects a "tricky" summer of business for Solskjaer, who has been linked with several players - including Ajax's teenage defender Matthijs de Ligt.
Solskjaer, who succeeded Jose Mourinho as United boss - initially on an interim basis - in December, has already begun to reshape his squad, with Swansea winger Daniel James, 21, heading to Old Trafford.
Rooney, United and England's all-time top-scorer, said: "The club needs to rebuild with younger players but they need to be good enough and I think the fans will understand that they are probably not going to compete for the Premier League next year.
"Let Ole have that time to build a team for the next two or three years that are going to compete at Premier League and Champions League level.
"It's down to teams like United, Chelsea, Arsenal and Tottenham and possibly Everton in the next two years to get to the level of Liverpool and Manchester City."
Rooney on England
England were beaten 3-1 by the Netherlands in the Nations League on Thursday, with extra-time errors from Ross Barkley and John Stones leading to goals.
Rooney believes the defeat will "help them in the long run" and hopes manager Gareth Southgate will continue to encourage his players to play out from the back.
"Everyone was disappointed not to go through but the team has got a lot of young players," he said.
"It would have been nice to lift the trophy but there were mistakes made on and off the pitch by the players and the manager."
Southgate opted to rest all six players - Liverpool trio Jordan Henderson, Trent Alexander-Arnold and Joe Gomez, and Tottenham's Eric Dier, Harry Kane and Dele Alli - who played in the Champions League final five days previously.
Rooney said: "I'm sure if Gareth had his way and looked back he possibly would have started the players that started in the Champions League final. I certainly would have.
"They were fit, and certainly the Liverpool players were coming off the momentum of winning the cup and that possibly would have made a difference."
Of the mistakes that ultimately cost England, he added: "I'm sure they won't happen again and if they do and that's the way the manager wants them to play, then he will take responsibility.
"If I was in Gareth's position I would encourage them to keep doing what they're doing as if you throw the blueprint out of the window then you're almost starting from scratch again.
Rooney on playing in the MLS and beyond
Rooney, who is in his second season in the MLS says he and his family are "enjoying" their time in the US, with the striker not recognised out in public as much as he is in England.
He says MLS is "getting bigger" but the salary cap restricts it from matching the big European leagues such as the Premier League and La Liga.
"They are cautious of dropping the salary cap as in the '90s it took a huge hit, lost out and had to fold," said Rooney, who scored his 300th club goal in May.
"It has potential to grow into one of the biggest leagues in the world."
Rooney intends to coach once he stops playing, and is inspired by his former England team-mates such as Steven Gerrard, Frank Lampard, Scott Parker and John Terry.
Former Liverpool captain Gerrard took charge of Scottish Premiership side Rangers in 2018, Lampard led Derby to the Championship play-off final in his first season in charge, Parker was appointed full-time Fulham boss at the end of the season and Terry is assistant manager at Premier League-bound Aston Villa.
He added: "As soon as I finish playing I'd like to go into management and see how I do as it's what I know.
"I wouldn't want to manage in the England set-up as my first job., I want to be involved day in day out and really work with the players."