How many of the same rifle/pistol do collectors possess and seek to accumulate?

Some, here, have amassed remarkable collections of dozens of the same rifle/pistol, separated merely by the date of production or minor changes in design. That is particularly so with the pre-war manufactures although there is likely to be a greater degree of variance, pre-1939, due to age, usage, originality of parts, condition, etc.

With more recent rifles/pistols, say from the '70s, there is likely to be less wear and tear and, for the most part, rather fewer models. So, how many of the same make and model do collectors seek to acquire?

It seems that the same make and model can vary to the extent that even pellets perform differently. Surely, however, two rifles/pistols of the same origin would be sufficient to provide a broad representation of the model, or is this number considered to be insufficient?

Do collectors seek to fire each item within their collection?

Do collectors collect as an investment?

What optimum numbers do collectors seek to accumulate before they turn their attention to another make?

Doubtless, the answers to these questions will vary according to the collector and different views will be held. It would be interesting to discover what motivates collectors. I wonder if any research has been conducted into these and allied questions.

Rgds to all,
A