How do you check writing speed?

Forgive me if I've missed this information in previous discussions, but how does everyone check their shorthand writing speed?

Many years ago, I had a set of Gregg dictation writing practice aids (cassettes, I think), but they must have disappeared in one of my moves. As I haven't seen anything comparable in eons, what does everyone do to check actual writing speed?

(by wordwrangler2 for everyone)