1. The Chazon Ish held that b'zman ha'zeh a husband need not light and extinguish the Shabbos candles for his wife - since our candles burn fine without preparation.
2. Some Mekuballim will not use a pen as a placeholder in a sefer because of "Lo sonif aleihem barzel."
3. RCK said that it may be proper to put labels on products that say "Birchaso She'Ha'Kol" and the like in Genizah (I guess that means disposal b'derech kavod, but he is very machmir in this area), since this is a halachah.