My tier 3 team is on 1-week point-Dev rotations. Roughly 1wk in 9 on primary, same again on secondary. They take about 2-3 calls per primary+secondary. I’m on Tier 4 in mgmt roster, and on call every other week. Take escalations and fall thrus every 3-4mths. Tier 4 also plays duty manager during events such as product launches.