Because I can....
I started getting multiple machines because when I went to trade in the "old one", it was cheaper to just buy the new one without the trade-in. They were having a great deal on new machines, so I kept the old one for my "workhorse". I have all Vikings, except for all my old antiques, the Singer that was my mother's from 1935, and several old machines that have been given to me. I don't often use the old ones, but all the Vikings are used for different purposes...the Diamond is exclusively set up for embroidery, the SE has the walking foot on it all the time. The Topaz 30 has the 1/4" foot on it for piecing. And the old Designer I is used for general purpose sewing.