Assuming they last 10 years (Apple stops selling them after 3 years and stops supporting 7 after that), you replace the battery ($79) and ear pads ($69) at the

Assuming they last 10 years (Apple stops selling them after 3 years and stops supporting 7 after that), you replace the battery ($79) and ear pads ($69) at the 5 year mark, that's (550+79+69)/120 months = ~$5.80/month or about $.20 per day.