The back-to-back Masters champion has reduced his playing commitments in recent years, and has only made two appearances since defending his title at Augusta in April.
"I've been doing this a long time. I've been on tour more than half of my life at this point," McIlroy told reporters on Wednesday. "I'll pick and choose my spots like I have been doing sort of the last 18 months to two years.
"Does it mean it makes it harder for myself to win the FedEx Cup or whatever the season-long title race is going to be called? Absolutely, but I'm okay with that because it brings balance to my life and lets me enjoy things outside of the game."
The 37-year-old also admitted that the Memorial, along with the Tiger Woods-hosted Genesis Invitational, is one of two tournaments he is particularly keen to win before the end of his career.
"I would say here and Tiger's event at Riviera, they're the two that I would love to win," McIlroy said, whose best finish in his 13 appearances at Muirfield Village was tied-fourth in 2016.
"I've been lucky enough to win at Bay Hill, but not while Arnold [Palmer] was alive. So I always thought it would be cool to win here and take that little walk up the hill off the 18th green and shake Jack's hand.
"Also, Jack and I share a nice history. We've known each other now for nearly 20 years, or I've known him for nearly 20 years. He's been nothing but great to me and my family. This is certainly one I would love to get done."