I Love Having Power (ha, ha, couldn’t resist that one). More seriously though, I agree with bdwaud above, it’s something that can be extremely useful, but only if you put in the time. I bought my power meter last August, second half of the season, and I only used it as a “data collector” at first. This was intentional, I knew that I had to learn how to use it. So for my last three races and many many rides I just collected data, yeah looked at it, but it didn’t mean much at first. What is 200W? Is it a lot, is it good? There is no right answer to that question, as usual it’s “it depends”. It depends on what you are doing at the moment, and your physical characteristics.
After the season I bought two books on the subject, and got to study a bit, Training and Racing with a Power Meter is the reference here, and very relevant when using TrainingPeaks; highly recommended. I feel that I will probably read that book again, or consult it from time to time. Do you think you would enjoy doing something like that? Do you like dissecting your ride and understanding (or trying to understand) why your performance was that way that day?. You are going to have to spend some time learning how to use it (the device itself is dead simple in most cases; it’s the software / data analytics that comes later)
I can’t stress this enough, there is a learning curve, and it’s steeper than learning about HR. For someone who hasn’t already “mastered” HR / Perceived exertion, I would say forget it for a while imho. I believe it can complicate things in that case, too much information at once. But once you learn what the numbers mean, power is awesome. I have found it invaluable for trainer workouts, you can really nail down the work that you actually do in your intervals, and the feedback is immediate. It’s also a great tool for pacing a race, if done right you have an approach at your disposal that is much more scientific and “accurate”.
But……one thing that I strongly believe is that you still need to collect and use HR the same way you would without a power meter. The PM can fail, and sometimes these devices can give you wrong data. I think if you can master how you feel + HR + Power then you have a ton of data about yourself, some more objective, some more subjective, but all important. I commute to work on my other bike, where I don’t have power, and I use a HR monitor there to make sure I’m in zone 1-2. I don’t think I would gain a lot from a power meter for those rides for instance. The PM is great for structured workouts and racing imho. So, is it needed? No. Is it useful? I think if you put in the time and like looking at numbers and understanding them, then yes absolutely it is.