I wouldn’t suggest folks go beyond 15 minutes of exposure per day. I’m not suggesting you can’t do harm to yourself by being in the sun too long. I think think you do need some. I do think that there should be limited exposure to sunlight. If you read up, the absorption of Vit-D by sunlight, it supposedly the best way to get it.
A supplement may be good for the 70+ set. A physician should know, but I would recommend a pharmacist first. The guys with doctorates in pharmacy have have pretty good handle on what works and what doesn’t.
They generally keep up on new meds, and can refer a person to the best med out there.
My personal rule of thumb is that nothing works as efficiently as you age so don’t expect the same results as a 30 year old.