I recently decided to add visualisations for one of my projects and found that there's too many data points to visualise them and not all of them matter. Since there's a lot of various data being visualised (as a pie chart, with an option to switch to a different chart), I decided that it might make sense to add "other" as an option. Now there's the question - how should I define a threshold at which "other" appears? Should it be more like a sum of all items below a specific percentage, should I be looking at the number of data points or would a combination of the two be most effective?

Example data might look like this:

Item  | Number of entries
-------------------------
Ex. 1 | 100
Ex. 2 |  50
Ex. 3 |  10
...   | ...
Ex.N-4|   1
Ex.N-3|   1
Ex.N-2|   1
Ex.N-1|   1
Ex. N |   1

In the context of the viewer, it's generally OK to sacrifice the Ex. N entries if necessary by grouping them together in order to highlight the main entries.