NW PA here, 35 miles from Lake Erie, it is humid here even on the best days.
Here are my facts. 12 year old Echo string trimmer. E10/87 stays in it from season to season even throughout the winter and it starts with 3 pulls every spring. Original spark plug and primer bulb. The same story is true for my 10 year old Echo leaf blower. 14 year old Toro snow blower. 11 year old Toro zero turn. 6 year old Poulan chain saw. The only piece of equipment that gives me problems is a Ryobi string trimmer but it is a ***** to start with any type of gas even now with a new carb, spark plug and fuel lines.
I also had a 70 Swinger 340 that spent 3 winters from Dec 1 to Apr 1 with 89 E10 in the carb and gas tank and it always started in the spring without any drama.
This year I switched my 66 440 Belvedere from EF 90 to E10 93 and the car performs better without any hot start problems and actually is giving me an increase of 1 1/2 mpg.
I can't explain why I don't have the problems other people have with E10 but I just considered myself lucky I guess.
Jerry