There are many successful and notable players who tune their response type and lower their deadzone settings in-game, promoting different adjustments these settings to see quick improvements in your gameplay makes sense! You want your controller to match your own play style and reaction speed, where the appropriate response type paired with lowering the deadzone allows you to react quicker and line up your shots easier. It's a built-in way to amp up your skill and you can fine tune it as you like. 

However, we have seen an increasing amount of thumbstick drift issues when playing on certain settings once they have been changed away from default. We'd like to break down why even professional players can have thumbstick drift with their controller even after adjusting their settings. 

A controllers' thumbstick input is read on two different axis, the X-axis for left and right, and the Y-axis for up and down. Deadzone settings are the default values measured by the distance-from-center that a thumbstick can move before the game will begin to register your controller’s input. Once the input threshold has been crossed, the input is translated to in-game movement and your character begins moving. 'Controller Deadzone' can then be described simply as, "How far does the thumbstick move before you move in-game?".

A deadzone of 0.2 or 20% will mean the character will not move until the thumbstick is moved at least a 20% distance from the center of the axis, or rather (±20,0). Naturally, this can translate into a more sluggish feeling response with fast-paced gameplay as the thumbstick must be moved further before something happens on screen. Conversely, a lower deadzone setting of 0.05 or 5%, that can feel 'snappy' because of the shorter distance the thumbstick needs to travel before an input is registered. It is important to keep in mind that this setting's function is entirely dependent on the physical condition of the controller internals such as the potentiometers.

The dreaded 'thumbstick drift' that plagues every controller user occurs when combination of all three components we discussed fall out of sync.

The component of the potentiometer that is most responsible for drift is a small ring of carbon that connects the electrical circuits of the thumbstick and allows inputs to be read. Over time and with use, the plastic parts that move (wipers) eventually wear down and shave enough carbon away to interfere with how well the potentiometer measures voltage. Once the carbon ring is too damaged to maintain a consistent connection, drift will start to occur. You may notice also after a long period of use, your thumbstick might have a little bit of wiggle to it, and is a result of other plastic components (saddle) being worn down as well.

Once a thumbstick mechanisms potentiometers have been worn out, which can happen due to a variety of reasons such as use over time or a 'rougher' playstyle, you will start to see jumps and inconsistencies in its values as the stick moves around. Where a thumbstick may have originally stayed (±4, ±3) at rest, may now read as (±8, ±4) at rest after heavy use. Taking into account certain deadzone settings and response types, a resting input of 0.08 or 8% will typically result in minor thumbstick drift across the screen.

Due to the circular input nature of thumbsticks and the variety of ways we play games, thumbstick components can deteriorate in all manners of ways, and no two controllers will develop drift at the same time or in the same manner because of this.