Anyone ever update their cards or do they just use the same data after the 1 yr update? I guess if I fished rivers etc but with most of our Texas reservoirs they only really change in depth so im wondering if it would be worth the 100 update.

thx

I keep both of my Navionics+ cards, my Hotmaps Platinum, and a few Navionics Mobile Apps updated and renewed after the Freshest Data subscriptions expire.

I do Navionics Sonar Charts so I want the most current maps.

With the Sonar Charts program that Navionics operates, they average around 20,000 updates per week, now granted I know that is all over the country and not just the lakes you may fish, but it does show you the amount of new information being added to the cards. I know every time I fish, I fill multiple 2GB cards of recordings to be added to the database with most of that being Toledo Bend, Rayburn and the Sabine River systems. These recordings are not just in bare areas where mapping did not exist, it is also areas where the contours could of changed due to flooding etc, so in my opinion it is a very useful tool to keep the cards and apps updated. The webapp online updates very often and keeps the most updated mapping that you can view for free if you want to compare what you are seeing on your cards.
http://webapp.navionics.com/#boating

I purchased a "freshest data" subscription thinking that is what I needed to update my platinum card. When I tried to update, my card didn't have enough memory for the sonar map update. Did I waste my money on the subscription and need to purchase another card? Any help appreciated.

You must have a Platinum card that is older than 2012.

Contact Navionics and they will send you the 16 GB card to update.

Just as a follow up, did you contact Navionics? This is a fairly common issue from when the cards went from 2GB to 16GB, so you will actually get the 16GB card for you update fee, plus still have the 2GB for a spare.