There are obvious connections in everything written above, but it takes the eyes to see it and ears to hear it.
Maintaining good mental hygiene requires serving others, which changes the universe, starting with perceptions, as I hear you say it. This is Truth.
Pain is the touchstone of spiritual growth. It prepares one for serving others, which breaks the juggernaut of self will, leading to liberation from life’s hells.
Mental hygiene is a fine balance between being patient, discerning, wise, reasonable, intelligent (read: not foolish or easily fooled), loving and kind. The obvious traps one might fall into regards poor mental health are unnecessary risk-taking behavior, promiscuousness, addictive or abusive behaviors, etc. Not to mention losing one's hair and teeth as obvious signs of declining-age hygiene.
I think older folks are at greater risk of this as age-related illnesses increase over time. Pain is usually a sign of a weakening physical being, whereas a person's mind can be sharp as long as he continues to take in knowledge and learn on an ongoing basis. The problem exists when old habits don't allow folks to think with cool heads, though perhaps one can collect their thoughts once the juggernaut of self-will, like a fever, breaks, and health is restored.
The other facet is, you don't usually put something in the oven only afterwards to immediately put it into the fridge. You usually serve what you've prepared to others, then consider saving the remainder where it can keep refrigerated until reheated again.
Also regards the juggernaut, you may be correct to some degree, though a vessel that was created for honorable purposes cannot change once it has been molded into its form. It can only resist additional molding, at which point the one who molds the vessel into its present shape must decide to start over and start with the clay once again, or discard the vessel. (Not my words. My teacher's words)
Pain is usually the result of overexertion, or resultant from straining against eventuality. Sometimes it seems futile to exert ourselves, but that is part of what is required of us. Perhaps the way I like to see this is, "work smarter, not harder." I usually don't follow what the world uses that molds us into who we are. Many people do, simply because that is how they perceive their work and how they interact with others.
Yet I think that old geezers (speaking for myself, and you if you'd like) such as ourselves need to break away from how the world expects us to conform to some of its debased standards, and be able to think for ourselves while providing for others by serving their needs.
Rather than seek a me-first attitude that is so prevalent in this world, we are actually being more upright in this manner and truthful regards how we stand firm against how the world tries to mold us to its standards.
While approaching things with an open-mind, there are some things that are unacceptable in my view that conflict with higher standards and laws that were written long before modern day. There exist certain codes of conduct and behavior one was expected to obey, not only for their own benefit, but for others folks they interacted with. Without describing these in detail, let's just say I adhere to a higher authority than what exists in today's laws. I realize that certain topics are off-limits and should not be part this forum, so I will happily bow out of this discussion if necessary.