There is a maintenance interval for a transmission fluid change, so it's not always an BS charge. The manual should tell you when to change it. Just changing the fluid is about the same as an oil change, but a drain and fill will get about 1/3 of it out, depending on the car. If you can do an oil change, you can do a transmission drain and fill. Do it three times, with a mix of driving in between to mix up the old/new fluid, if you think you need a full flush. It will likely help your transmission last longer if the fluid is changed regularly. Someone will probably chime in and say that if you wait too long, replacing the fluid could damage the transmission. That's true if you're way over the recommended service interval, but otherwise you should be OK.
Also, from what I've read, Honda doesn't recommend a transmission fluid flush, they say to do a drain and fill three times. Flushing it (with pressure) can damage things or dislodge stuff that you don't want to dislodge.
There's also a maintenance interval for brake fluid, spark plugs, air filters, timing belt, coolant etc. Replacing coolant refreshes the corrosion inhibiting additives. Replacing brake fluid gets moisture out of the system (it's sealed, but not perfectly). Read the manual, it should spell out all the regular maintenance intervals.
You could try spark plugs first and see if that fixes the engine issues. For air filters, look at them and see if they look dirty. If so, replace.
Sadly, between people dismissing regular maintenance, manufacturers pushing maintenance schedules out as long as possible ("No scheduled tune-ups for 100,000 miles) and shops pushing service when it's not necessary as much as when it is (crying wolf), you end up with cars that don't get much or and maintenance besides oil changes for the first few years then suddenly have a lot of problems after 100,000 miles.