Navionics app.

[Bduck]

I have Navionics for the GPS side of my sonar unit. Bought it as part of the package with the new sonar unit. Navionics comes on a micro sd card with a years subscription. I do the updates for that year but rarely to never renew after expiration. It doesn't effect my sd card, if I were to possibly use this GPS on the road routing it might be worth the the updates since new roads are always built. I haven't seen much in changes in most lakes we venture to here. I have seen the formats change in some cards. In my opinion no need to update lake maps after a year. I do have a TomTom for our vehicles that have a lifetime subscription. The lifetime doesn't include your lifetime, only the unit itself. I have an older TomTom also that's  15yrs+ old that can no longer take updates to its memory but still works. If the app you have is for another device such as a cell phone I would think since you purchased that app it that it will continue to operate after subscription expires.