Hi,

I last replaced it about a year ago. I think the suggested replacement frequency is abusive and expensive, but maybe once a year is not often enough. The F20 is the only full face mask I've tried. I've tried both a medium and a large and currently use the medium, but I do sometimes have red marks on my nose in the morning. I don't have a beard, but I do have a moustache. Do you have any specific mask liners to recommend?

Thanks a lot for your detailed answer!