E and -κε

I would like to explain the difference in meaning and use between the conjunction e and the conjunctional suffix -κε, both meaning "and".

First of all, let's look at the way the two words are used to connect two words:

Cαнδεр e Δαн.
Cαнδεр Δαнκε.

Here, both sentences mean the same (although they do not make any sense): "Sander and Daan". The only difference is that -κε is semantically closer.
Only when we put them in a sentence, can we see some significant differences.

Verbs

When used with verbs, both options mean practically the same. The difference between 'ειδω e ᴧeгω' and 'ειδω ᴧeгοκε' is minimal, although the first is translated "I see and I say", and the second could be translated as "I see and say", emphasising that it is done at the same time. Accordingly, Δαн ειδιc ᴧeгοκε ("Daan sees and-I-say") would make no sense.

Nouns

Between nouns, -κε is used to indicate some sort of bond between the two, for instance when describing a well-known or logical pair (e.g. παтрο мεтακε - "father and mother").

List

More clear is the difference when they are both used within a list of nouns or verbs. Here, -κε would indicate a subgroup. E.g.: παтрο мεтακε e δαмκιc - "father and mother, and the servant", thus (Father && Mother) && Servant.

Some example sentences:

Παтрο мεтακε ειδεc e ᴧeгεc. - Father and mother see and say.
Δαн e παтрο мεтακε ᴧeгεc αυтeεc. - Daan and (father and mother) say other things. Thus: Daan and his parents do not agree.