Mashing Theory for Pokemon

In Pokemon Gen 1, text box windows are on 3 frame long cycles.  In order to clear the box properly, you need to press A or B during the first 3 frame window after all the text is printed.  You can alternate A and B to double the number of windows you can hit, and the game runs at 59.7275 fps.  So the first key of mashing theory is that in order to hit every conceivable 3 frame window, you need to mash A and B 3 frames apart, each at a rate of 59.7275/6 (~9.95) presses per second. You can guarantee hitting every box within the first 2 windows by halving the rate.  For end of Paragraph boxes that don't have the "ding" when you clear them, you have to press B and not A to clear them the fastest way, so this level of timing becomes very difficult.

This is obviously not feasible to maintain over the course of an entire run, but it can be done in short bursts to maximize the effectiveness of your mashing.  So the second key is that as you practice, you should get a feel for when text boxes come up, and only mash at that high rate as they finish.  At the highest level of play, it is almost essential to get a precise feel for the text boxes so that you don't have to mash constantly and burn out your hands, especially with the end of paragraph boxes since you can't clear them effectively with mashing and really need a feel for timing them with a B press.  I liken the process for getting a feel to how you'll see hitters and fielders in Baseball sway their center of gravity between their feet as they wait for the ball to arrive.  You can sway your fingers in anticipation of having to clear a box and be ready to press the buttons at the right time.

In Gen 3 this all gets thrown out the window and inputs are fully 60fps.  Timing inputs at 60fps is as much of a pain as trying to mash as fast as possible, but it ends up being much more effective in Gen 3 since you'll miss the first possible frame by wildly varying amounts trying to mash as fast as you can without the 3 frame windows for 2+ hours.

You can also just be Pokeguy to solve mashing problems.