Obviously, states like AZ and FL that are farther south don't need DST.
Florida has DST, although it and several other eastern states have talked about getting rid of it, effectively moving to Atlantic Time (UTC-4) year-round.
Hawaii is the other state that doesn't observe DST.
Having lived where sunrise and sunset only varied by a few minutes all year long, I appreciate the consistency of having a single zone permanently.
I take it you're talking about Quito. I would think that, by definition, anything along the Equator would have its sunrise and sunset at exactly the same time every day. I know the Earth isn't exactly a perfect sphere, so I'm guessing that's why there's a bit of variation.