Your question will almost certainly be closed as a duplicate of Can you help me with my capacity planning?Can you help me with my capacity planning?.
This sort of question, and variants of it, pop up so frequently that the community generally does not want to post the same answers over and over, thus the three canonical questions about capacity planning. Almost all such questions are closed as duplicates of one of these three questions. (The other two focus specifically on web servers and databases.)
Since the answers to these questions explain how to determine what the correct scale is for virtually any particular use case, it's unlikely that this question would last very long.