I only change it if it needs it. I have over 3 gallons on the original factory plug that came in my Novarossi Rex Legend 28-8RT (now called the Truggy 28-8RT under the Novarossi name instead of the Rex name). At $15 a pop or better, I’ll run them until they won’t run anymore (reliably). If I were racing specifically, I might think differently.. I mean.. money is no object to sponsored racers, so their opinions are very much biased and less trustworthy.