Jeez, I never remembered boilerplate stuff anyway. Losing grasp of your commonly used, slightly more involved code idioms in your key languages would probably be where I’d draw the ‘be concerned’ line. Like if I get into a car after years of only using public transit, I wouldn’t be too worried if I couldn’t immediately use a standard transmission smoothly. If I no longer could intuitively interact with urban traffic or merge onto a highway, I’d be a lot more concerned.