If a Blue or Bronze member has had no activity in 36 consecutive months but they are part of an HHA which has a Gold or Silver member their Avios will be protected as long as there is an active Gold or Silver in the HHA. Other than that, make sure you keep an eye on this and ensure all accounts have some activity occasionally – of course, the easiest way to do that is a redemption due to the formula above.
My wife is a Blue. She never has activity. I am a Silver with last activity in June. We have a household account.
A few months ago, she received an email saying that her Avios would expire in 6 months.
Somewhat moot (I hope) for the next three years, because I am about to do a redemption for me, which if I understand the first post of this thread correctly, will result in some of her Avios being deducted which should then reset the 36 month timer.
Still it is annoying. Thoughts?