Very, very, very important as not to leave this responsibility to another family member when you pass away. What you like, consider to have monetary or sentimental value, will not be the same with a family member left behind responsible for the downsizing. When the eldest sibling passed away unexpectedly, the siblings were left with downsizing due to no children or spouse to consider "value". Man you're talking about chinaware, silverware, fine rugs and clothes, restaurant size pots and pans. Siblings, nieces, nephews don't know what to do with that kind of stuff. Who has a China cabinet today? Young folks will look at you and say, what is a China cabinet, is that some place where you keep your paper plates? Some will probably say, I don't want anything to do with that country.
So yes, I will totally agree to downsize while you can and be sad now to spare family members the frustration of being sad later.