I think the rule for spices really ought to be revised to "only buy what you can use within 6 months to a year, as much as possible."
I don't know how common this is everywhere else, but my grocery store has a large bulk foods section, complete with an aisle of bulk spices. I did the math and determined that, ounce for ounce, the bulk spices are at least 1/4 the cost of bottled (and many of them are way cheaper than that in comparison). It looks scary to buy spices that cost $20+/pound, until you realize that you're buying about a tablespoon and it'll cost you a few cents. It also means that we can buy only what we think we'll need, which is very helpful for both spices we use only occasionally and spices we use in everything. It means we can buy massive quantities of garlic powder at once, but only little bits of things like baking powder that I only ever use once in a blue moon.
As for things I do against prevailing advice...I never wash my clothes in anything but cold water. I grew up doing it for environmental reasons (it saves electricity), and have never noticed my stuff to not get clean. I also seriously downgrade the amount of laundry detergent that is recommended. And I don't separate colors, unless it's something like a brand new pair of dark wash jeans. The only laundry sorting I do is "stuff that can be tumble dried" and "stuff that needs to be hung up." I only even do that much because it means my husband can do laundry without me having to be around, while also avoiding major laundry disasters.
I don't own much that is dry clean only, but I don't necessarily shy away from washing it. I have a silk dress that I very successfully washed using the delicate cycle and Woolite. I didn't spin it dry, but squeezed the water out by rolling it up in a towel, then hung it up in the shower to dry the rest of the way. I think I had a couple of pulled-loose threads (the outer layer is chiffon), but I was able to wiggle those back into place. It also had a ton of lint on it from the towel, but that wasn't hard to get off once it dried.
My mother actually told me that there isn't any reason at all to dry clean silk, and if the dry cleaner doesn't handle it properly, they are more than capable of ruining it. The only thing you have to be careful about with silk is absolutely avoiding all heat when it is even the slightest bit wet, since that makes it shrink. It's also just a delicate fabric that tears easily in general, so you have to handle it carefully. But as long as there's no heat involved, there's no reason you can't get silk wet.