My understanding as how it works is that if you or your wife have been paying into Social Security and your wife starts collecting Social Security Benefits (your wife being over 62), then your wife will have to start receiving Medicare Benefits on Feb 1, 2017. But if your wife postpones receiving Social Securty Benefits, then maybe you stay with private insurance(you must check on this with Social Security and also your private insurer since your Medicare premiums might be higher at a later date and also your private insurer may require your wife to be on Medicare since it lowers their risk.). Premiums for Medicare are also deducted from Social Security Benefits. In other words, your wife must go on Medicare during the month she turns 65 if she receives Social Security and you must go on Medicare at 65 also. Medicare pays 80% of the bill, and private insurance pays 20%.