How far should I estimate in quarter level (net sales and EBIT)?
Current year
Current year has to be estimated in quarter level. In fact, there is no full-year estimate cell available.
Second estimate years
In normal case it is enough to have full-year estimates for the second year. But when year end is getting closer, you might consider making quarterly estimates also for the second year.
Quarter estimates for the following year should be made at the latest before running YearChange macro. In technical aspect you can still ignore those estimates but then the year change would cause a significant change to fair value as (new) current year growth and EBIT-% would become 0.
Third and fourth estimate years
You can always stay in full-year level when you make net sales and EBIT estimates for the third and fourth estimate years. The reason why there even is a possibility to estimate in quarter level, is mainly technical.
Quarter estimates dominate
Please, remember that if you enter both quarter and full-year estimate, the latter is ignored.