@naiad Your question hits on a bigger subject I think: Software reliability / backward compatibility as well as software stability within a multi-year project. The former is just something that comes with the territory of software and I’ve never heard of an app that stays perfectly backward compatible over the course of a decade or more.
Thankfully Blender has a big benefit in always letting us access previous versions. So if your year-long sculpt doesn’t open or perform properly in a new version, just go back to the version you created it with.
As for using Blender on a multi-year project, I’ve been a part of such projects and the general rule is to stick with the same version of Blender throughout. If there’s significant tool improvements worth switching, the new version needs to be testing and eased into to be cautious of serious compatibility issues. Blender is quite good about backward compatibility but still it’s something to be mindful of.
No matter what there’s some risk involved with working digitally (though a lot less than physically). So long as you save often and/or backup your files, you really shouldn’t have trouble mitigating these risks enough to complete projects effectively. Just don’t be paralyzed by the fear of such risks. Truly one of the most valuable skills I’ve developed is adaptability and problem solving. Soooo much of computer graphics is problem solving. Those unable to roll with the punches don’t make it far.
