Normal.. or excess attic humidity?

I am a new DIY , poster, by necessity, dad was a carpenter & grandfather a pro electrician biz… Re roofing my 1987 Simple 2 panel country colonial roof. I’ll measure the pitch ratio if needed:
No leakage complaint, just dried up degradation of original tab shingles. When I flash-lighted inside the attic, the north panel interior chipboard and plywood seemed…
White. Not showing individual drip trails…The south facing seemed (normal)faded brown yellow. Does this indicate humidity ? The east/west ridge vent runs most of the 40 foot length, it’s a baffled aluminium design. The same north south garage ridge does
leak a little in the wind driven central new york winter storms a, little… (I positioned a line of plastic garbage can lids and old sno coasters for the ocasional drip.) No discoloration of the interior family/garage roof . The 12" plywood soffits show a 2 1/2" da. screen vent every 3 1/2 feet…
Oh… and the bathroom and kitchen exhaust pipes,(aluminum) vents run horizontal only toward the north panel…
a) Need I blow out dust in the soffit vents from exterior
b) Change the Aluminum ridge vent/baffle or keep ?.
It is exposed black painted, subtle, and is not shingle topped…
c) The roof panels seem sound, just wondering why
the one side looks more aged
d) I’m only a few dozen shingles from either recyling or replacing the original vent.
e) There were no other air relief vents on side gables.

Any explanations would help, and was the original ridge vent good for a few more years? Can submit pictures , thanks for comments.

Are you saying you have already ripped of and re-shingled?

My roof is almost re-shingled, 4 feet left to the peak… I question whether to maintain the original aluminum ridge vent , as it has served well, and why only the north interior side of the attic shows
a color change inside. Never any snow or rain leaks or issues, just old tabs being changed out.
Pictures available…

You may have a slight moisture and mold problem on the north side of the attic.
The south side is getting more heat, therefore keeping the moisture in check on that side.

Without doing the math, I think you need more soffit ventilation.
Also, if your prevailing wind is from the west, I think you would benefit from the addition of gable vents.

While you entered a response I was at Lowe’s looking at the variety of soffit plug and gable vents, and found the Owens Oakridge ridge pack of ‘topping’ shingles ( $ 40)and I saw my same original folded ridge vent is still popular, so that will stay. Does it matter if a 12 x18 or similar gable vent install windward or on the quieter, cooler east side ? A new garage gable vent would be a an attractive design detail, next spring.Thanks again

Gable vents are not recomended in conjunction with soffit intake,and ridge vent exaust.

Pictures would be good.

I would recommend a gable vent at both ends.

Basic Roof Ventilation