I keep my wheels in a metal drawer on the cart that holds the Wheelwriter.
Each wheel has the typeface printed on it along with pitch information. PS wheels are for proportionally spaced Wheelwriters which this one is no. Being made of plastic I don't know how rugged the wheels are, but golf balls for the Selectric are also made of plastic and those last a long time.
A cursory look at printwheels on a major online auction site shows many wheels available, but the prices are not what I would be willing to pay.
This is my current wheel list with sample type in Rev. Munk format (sans sentence):
That Courier 15 is tiny!
This typewriter was a donation from a secretary (now retired) at Alhambra. Janet was her name and this was her departed mother's typewriter. She was, from what I remember, an active participant in her church and a regular contributor to the Sunday bulletin. Not pictured is a paper support arm that slid into the vented slots in the back. The one that I have is broken and just falls out. It's of limited use anyway.
I dust this typewriter off for form-filling. It does the work admirably. I love how you set the margins; just a button press.
A great typewriter if you have a stash of ribbons (I am down to my last two).