Starmate Lifetime subscription

I bought a used Sirius Starmate months ago I recently put batteries in and tested it, it worked and found stations. Can I assume it has a lifetime subscription?

Maybe but, you wont know until you leave it turned on for a few hours. These radios receive signals from the satellite every x number of hours that tell the radio whether the subscription is active or not. If its a lifetime it will work forever, if its an old month to month sub, it will turn itself off the next time it receives a subscription check signal.

I had luck where I would only turn the radio on every so often and it lasted over a year before it was finally deactivated.