# Criteria to set STL s.window width

Using R to perform STL decomposition, s.window con­trols how rapidly the sea­sonal com­po­nent can change. Small val­ues allow more rapid change. Set­ting the sea­sonal win­dow to be infi­nite is equiv­a­lent to forc­ing the sea­sonal com­po­nent to be peri­odic (i.e., iden­ti­cal across years).

My questions:

1. If I have a monthly time series (that is frequency equal to $12$), what criteria should be used to set s.window?

2. Is there any link between that and the time series frequency?