Novak Djokovic: Older players like us need to be wiser in scheduling

Last time that the Big Four competed in the same tournament was 2017 Wimbledon.
Is it just bad luck with injuries, or is it that the players are also planning their schedules better? In his press conference at Cincinnati, Novak Djokovic replied:
'I guess it's just age, in a way, as well.
And though I think age is just a number, but still, most of us players that were winning most of the big tournaments in the last decade, we have also kind of.
I don't want to say an expired date with our body, but just times when you need to slow things down a little bit and be, I guess, wiser in terms of approach the scheduling when you want to play your best.
It's normal to expect that you have new faces on the tour, (Alexander) Zverev, who is now established top 3, 4, 5 player in the world for quite a long time.
(Stefanos) Tsitsipas, (Borna) Coric, (Denis) Shapovalov, you have a lot of those NextGen players that are making their mark in the tennis, and this is the new generation this is coming in.
I don't think that's something weird or unexpected. It had to happen. But still, I think the top guys are hanging in there, and it's a good mix now that we have -- I feel like it's good times for men's tennis.'
In an interview to RTS, Djokovic also commented on what his coach Marian Vajda means to him.
'Marian is more than a coach for me. He is part of the family. He has been with me for the last 12-13 years.
He is the man on whom I can always rely, with whom I shared the great and difficult moments in my life, and I am very glad he is here (in Cincinnati),' Djokovic said.