Here are our experiences on the major hotel chains.

IHG has points never expire policy.

Marriott does not enforce the expiration policy, nor the Silver status which seems once there, it is there forever even without activity or credit card ownership.

So was Hyatt but that would change after the devaluation announcement this year. They said they would start enforcing the expiration policy starting this year.

Both HHonor and SPG delist your account after 12 months non-activity. However on HHonors forum there are reports that a phone call to HHonors the accounts were promptly reactivated and points restored, WITHOUT a fee.

Both used to have very narrowly defined activities in order to keep account alive - namely only paid stay and CC charges. Though they have changed that since last year, now an award stay would take care of that from what I understand but not 100% verified.