PLS chart, page-16990

" In/out of a covered call isn't really a good use of your money as its covered so you may as well hold to expiry and get the full credit. "

This is not entirely correct, say if you sell a call 3mths expiry for say $2, then 3weeks later or even a matter of days sometimes that call can be worth say 20c (believe me with stocks like BHP / WDS etc can happen ) why would you not buy back & pocket $1.80 profit in say 10 trading days , rather than wait 3 mths to MAYBE have that option to expire without being exercised & get 20c more, in that 2mths & 2 weeks you could trade that same amount of stock many times.
Have had many trades over the yrs that seemed like would expire & collect full premium a day or so away from expiry date, only for some unforeseen reason to make the stock rally & all of a sudden they are in the money, so this is where stock direction comes very much into play, & you won't go broke taking a profit.
It isn't "your money" until the trade is closed, expired, exercised.
Everyone has their own way of trading management.