I have a modest collection, I call it my museum. I love my boards and will keep many of them until I am forced to move, or I die. My current use boards get sold when I get tired of them. I am actually selling and buying right now.
I have the worst time selling boards. Although the truth is that it's never as bad as I expect and actually feels pretty liberating letting them go as long as it's not a board you're really in love with.
The boards I keep are those that have meant the most to me over the last 55 years. I don't have many(about half a dozen)and three of those I have owned for over 40 years. Space is always a problem with surfboards. It's not like a collection of baseball cards where you can put them in a drawer. There is about another three that I wouldn't mind having, but I doubt I could even find them let alone the expense and where to store them. Although not my main motivation, some of these boards are worth much more that I paid for them so it's not like it was an expense.