How you rate: 15 words, average; 20, good; 25, very good; 30, excellent.
Source: The Times
Answers on the continuation page.
dire, drey, drip, dry, dyer, fiery, fir, fire, fried, fry, fyrd, ire, per, peri, pier, prey, pride, pry, pyre, red, ref, reify, rep, rid, ride, rife, rip, ripe, rye
perfidy is the word using all the letters (which I didn’t get, Susan!).