Here is a really good article about the longevity of inkjet fine art prints.
Be assured that all my prints are done on best quality archival museum standard papers and I will recommend plex frames with extra UV protection. Your print will likely see you out.
I have decided also to offer the files for sale for private use only which means collectors can print their own copies if the hardcopy fades.
I will retain the copyright of course but this would remove the issue of longevity for future generations and allowing for bequests to private owners.