On a nitro RC there are a lot of little things you have to do to get it ready to run and after-run maintenance tasks that need to be done before you put your RC away for the day. But while you're running your RC the one thing you're likely to be constantly messing around with are the fuel adjustments. You might get it set just right one day and think you'll never have to change it, but that's not true. Changes in the weather as well as track conditions or changes in your brand of fuel mean that you may have to be making lots of little fuel adjustments -- leaning it out, richening it up to get the right settings for that day and location.