Part of the reason I have so many (23) is I pick up older machines and give them new life. I loan them out to Guild members and for our Guild Quilt camp. This way we don't need to supply our REALLY good machines for others to use. That could lead to bad tempers.
I also teach young people the basics of sewing (in case you haven't noticed they no longer teach home economics)and I have even gifted a machine or two to those who have really taken to sewing.
Of course there are those which are my special babies...hehe