under likert-scale questionaire
Never
Rarely
Sometimes
Often
Always
Can we add the results of Never and Rarely=?
Often+Always=? for the purpose of data interpretation purpose?
Dear Temesgen, yes! Numerically you can simply collapse both categories into one (e.g., almost never & almost always). The question would be what these new categories mean then, that is, whether they are still meaningful to you research question. Also, in quantitative research, we usually want to keep all the available data information and not make categories broader, and therefore less informative, than we have to. So I suggest you keep the categories as they are.
From the use of frequency adverbs, I guess you are after numbers, frequencies from your questionnaire. I don't think it is useless to use NEVER, ALMOST NEVER, SOMETIMES, ALMOST ALWAYS, and ALWAYS. The practice with Lickert Scale is to keep ODD numbers of data collection categories such as 5, 7, 9, etc. The rule is that odd numbers minimize loss of data.