Extra insulation won't really help cool your attic directly—that's ventilation's job—but it does keep heat from seeping down into your living space. If your ventilation setup is already solid, piling on more insulation probably won't extend shingle life noticeably. Had a similar situation myself; after upgrading vents, I added insulation mainly for comfort and energy savings downstairs. Didn't see any real difference up top. Good ventilation's the key factor for shingles, insulation's more about your indoor comfort and energy bills.
You're spot-on about ventilation being the main factor for shingle longevity. Insulation is more like icing on the cake—great for comfort and energy savings, but not really a game changer up top. One thing I'd add is, if you're considering upgrading your roofing materials, definitely look into options designed to reflect heat better (like lighter-colored shingles or reflective coatings). I've seen homeowners get solid results from those tweaks, especially in hotter climates.
Also, don't underestimate regular maintenance. Keeping gutters clear and checking for minor damage after storms can stretch your roof's lifespan quite a bit. Sounds like you've already done your homework though—nice job thinking it through before splurging.
Totally agree about reflective shingles—I switched to lighter-colored ones a few years back and noticed a real difference in attic temps during summer. Not a miracle fix, but worth the extra bucks if heat's an issue in your area. Regular checks after storms saved me some headaches too.
"Not a miracle fix, but worth the extra bucks if heat's an issue in your area."
Fair point, but before jumping into pricier shingles, I'd suggest starting with ventilation. I was skeptical at first too, but adding a ridge vent and improving airflow made a noticeable difference in my attic temps without breaking the bank. Reflective shingles might help, sure, but tackling ventilation first could save you some cash... and you might find that's enough to keep things comfortable. Just my two cents from a fellow budget-conscious homeowner.
Ventilation made a huge difference for us too. Before we fixed ours, the upstairs rooms felt like ovens by mid-afternoon. Thought about pricier shingles, but improving airflow first was enough to cool things down noticeably... saved us a decent chunk of change.
