I have gotten the very definite impression

that a number of the runners here who are far more experienced and more informed than I am
:flowerforyou: feel like speedwork is unnecessary for beginning (or any?) long distance runners to increase speed. My curiosity is piqued. I have been doing speedwork once a week for most of the past year, and I feel like it is really helpful: (1) it gives me a chance to feel what various race paces would feel like; (2) it accustoms my body to a more elevated heart rate, more rapid breathing, etc., and (3) it gives me the opportunity to figure out a good pace to aim for in my next race.
Of course, "versus" is in quotes in my subject because it's not really an either/or - I agree that increasing mileage will also make you faster. But at a certain point, a lot of us just max out the time we have available to work out, and at that point, it seems like speedwork provides another opportunity to further develop. I also understand that people may be pushing themselves too hard on the miles they DO, and are maybe not putting in the total miles they could as a result. I am assuming here that a hypothetical runner is running as much as they have time to run.
I'm interested in the reasons why those of you who recommend increasing mileage in preference to speedwork do so. I enjoy it, so I will probably keep doing it, but I don't want to be recommending it to other people if it's really not useful!