Both mean 'more far'.
Everyone thinks about the group as one person. Every one thinks about the group as lots of different people.
Early means before it was expected. Earlier means it was done before now.
Envious and you want something. Jealous and you are afraid of something.
Either when talking about two things. Neither when talking negatively about two things.
If it is very important, it is essential. If it is needed, it is necessary.
Experience is about skills. Experiences is about things that happened.
