Is it real to assign one ore more specific extrafields in different categories?
For example, I have extrafields like price, adress, city, etc - this extrafields must be assign to ALL my categories. Also I have extrafields, which must be assign to SPECIFIC categories.
So, I think extrafileds must have new parameter - "assign to category" or "display in category".
Because now, I have 30 categories, it means I have 30 extrafileds groups, and also it means I have 30 extrafileds price, 30 extrafileds adress, 30 extrafileds city instead of one...

Hi. Curently you can only assign group of extra fields to categories. So you are gonna need two groups.

Not quite.
I need 30 groups x 30 extra fields = 900 same extra fields.

But if it will be possible, I can create 20 generic extra fields and assign them to 30 categories (without any groups) - I no need to create 20 same groups with very little differences.
And then I can create 2-3 different specific extra fields and assign them to 30 different categories.

This method use adsmanager component, and this very, very, very comfortably:

If each of your categories have different extra fields then you do need 30 groups. There is no other way achieving this.

Lefteris Kavadas wrote: If each of your categories have different extra fields then you do need 30 groups. There is no other way achieving this.

Not each. All categories have 27 same fields, and only 3 different. ;)
Your method is not right.
Need to assign every extrafileds to existing categories.
No need groups, it is inconvenient.
80-90% fields are same...
No sense to create fields like adress or price or square in 30 groups.
Needs create only one field and assign them to 30 categories )))))))))))))
It's great, easy and perfect.
This feature make k2 really the best !!!
But ofcourse, this only your choise B)