When your ticket is cancelled or significantly changed involuntarily (by the airline instead of yourself), ANA refunds the ticket and resets the expiration of the miles. This happened to me when the TYO-HKG segment of my award flight was cancelled during the pandemic, which revived my miles for three more years.
Although much of the world doesn't take the pandemic that seriously now, I'm sure you can look somewhere to find flight routes that are "fragile". United tends to adjust their schedule 3-4 months prior, which may cause you to miss a tight connection in your dozen of flight segments. Just saying (*wink*)...