I have five lenses distributed between two turrets, and switch between them.
50, 80, 90, 105 and 150mm focal lengths.
The loaded turrets are easy to store and easy to use.
Now if only I could get my hands on that 63mm Nikor that I'd like, for a price I'm willing to pay, my turrets would be complete.
They are definitely worthwhile.
One caution though - the turrets come in two versions, and only the thinner one works (barely) with some of the 50mm lenses.