You misunderstand the rating of fuel in US/Canada at the pump. The "octane" rating you see is the AKI (Anti-Knock Index). It is about 4-5 points below Europe Octane rating. Europe octane 92 fuel is the same as US 87 fuel. Most car labeling for North America will reflect that if you look at the fuel door. Premium fuel with rating of 94+ in North America is almost like race fuel. No one need that for DD, I only use that when I am going to the track.
I personally will not use E10 fuel if I can help it, not for the reason that you are thinking. Almost all modern engine/parts can use E10 fuel with no problem. I dont use E10 because I don't drive enough. I dont think I refuel the tank once per month per car.
E10 fuel should not be in your tank for more than 2-3 weeks depending on how busy the gas station you bought your fuel from. Ethanol will absorb any water in tank (yours or the station) and moisture from the air. This happens quickly and will actually lower your overall octane level by up to 15 points. So, an older (3-4weeks) E10 fuel with octane level of 94 is like running your engine with octane 80 fuel because of the water in the fuel. We all know it is not good to have water in the engine. E10 fuel also lead to faster fuel separation. I have a choice where I am from and I dont have to buy E10 fuel. Some states only have E10 fuel. Remember E10 was introduce to "decreasing US dependence on foreign oil" and to provide a subsidizes to the farmer. It wasnt put in place to help the car owners. A non E10 fuel with same octane rating as an E10 will be more expensive. If you must use E10 fuel, use it quickly.