once a year they service their equipment they just show up when ever I think an appointment works better it does for me any way as the guy was leaving last Friday he said how about 2 on Friday I said how about calling me to set an appointment up well I called on Monday jan.14 the person hat answered said the guy that does them calls you well here it is jan. 15 I called again the girl said just a min she gave the guy the info talked to my insurance company yesterday and Lincare already put in for payment and it was approved