You don't need fuel cleaner very often, really. As long as you use quality gas for Top Tiers, you shouldn't have any issue to begin with.
Oh, and don't drive your car like a granny all the time. When you are going onto the highway, floor it. The occasional hard driving can clean out a bit of carbon.
With 8th Gen V6 AT, make sure you have the latest revision of the VCM update. This supposedly helps. If you are very paranoid, you can just disable it.
As for the Seafoam in the intake/vacuum line thing, I heard that water can do the same thing. You would suck the water into the vacuum line slowly like you do with Seafoam. Water is a lot cheaper, of course, but the Seafoam spray is a lot easier to use.
I bought a funnel and a 16oz of can of Seafoam. I poured it into the gas tank and then filled it up with Chevron 91 octane. How soon can I notice any results, assuming the fuel system did need some cleaning. My 08 Accord only has 54k miles. Thanks.
The typical procedure is 1/3 in the gas tank, 1/3 in the crankcase, and the rest goes into the vacuum line(although they have a spray that does this now). 1 can in the gas tank is a bit too much, but you should be fine.
You shouldn't really notice anything. You
may get a tiny MPG improvement, but that's really it. It's mostly preventive.
It's unnecessary to drive mad when you are doing this, as it is not required to do so. You can just leave it in park and rev the heck out of the engine until all of the carbon smoke comes out. That's what I did and many other Accord owners did on youtube.
Rev the engine to redline in P/N/neutral is bad for it. There is a difference in revving the engine up with and without load. Driving a car to redline is nothing to be afraid of, but there is a good reason why AT Accords won't let you rev past 5k RPM in P.
Just find the closest highway ramp near you, and there.