Who I have the same questioned this topic

I have been using Verizon Messaging on wifi iPad and desktop for quite some time - as I had a "dumbphone" and needed quicker access to communicate via text. Now I have a new iphone. I turned off iMessage in favor of Verizon's app since I can access across all devices. HOWEVER I now realize messages vanish after 90 days.

I need a way to keep/store and access images and messages texted to me longer than that. Other than downloading/saving images 1-by-1, how can I save or archive my messages?

Or do I just use Apple's iMessage which will allow me to keep my stuff?