At United off the top of my head it’s a rolling 12 month period. At 5 distinct instances of sick calls in 12 months you can get a call and/or email checking up on you advising further sick calls can get you put on attendance monitoring. Each sick call from there escalates to mandatory discussions. At 8
is when discipline including termination can happen. I haven’t gotten high enough to press to test, but I assume around 5 is when asking for doctors notes could be a factor. I don’t know if providing them is obligatory or not.