We recommend you have a single mailing list with all your contacts and use segments and tags to target them. This is far more flexible and effective in the long run, as you're free to slice and dice your list using as many segments or tags as needed!
Nevertheless, sometimes going for fully separated mailing lists may be preferable (especially for agencies dealing with different brands).
This means you can create multiple lists in E-goi, up to a maximum set by your acccount's service level:
5001 plan (paid with love): 15 lists
Starter: 25 lists
Pro: 50 lists
If you exceed your limit and really, really need more, you can ei ther upgrade to a higher-level account or delete one of your lists.