The definition of a rule is  an official regulation, code of regulations or set practice. An example of a rule is that a red light means stop. An example of a rule is an employer demanding their employees arrive at 8am.
The average cost for a fuel injector replacement is between $231 to $342. Labor costs are estimated between $168 to $213 while parts are priced between $63 to $129. Get a personalized estimate based on your location and specific car.
My injectors all run. I'm just concerned that one doesn't run well enough. I had planned mimicking the youtube video DIY Fuel injectors cleaning but after the Subaru dealership quoted the O-rings at $9.51/ea for a total of $76 I thought maybe a run of fuel injector cleaners would be in order. A 32oz bottle of Lucas Fuel Treatment will last for ~2100 miles and was only $12.