It's what a well run club would do. City could squeeze out more from Laporte/ Mahrez, Liverpool Henderson/Fabinho but they've recouped good fee's for lads around 30.
Varane will be 31 and he's played in 47/77 possible premier league games. Top player when he's fit, absolutely not now but if Saudi come in for him you push him out the door, no brainer. Same with Casemiro, he'll be 32. He's more durable though, if he has a top season and plays 50 times maybe you don't but in any case it should be explored.