I often use the following way of explaining time estimates. “If I was to do thing X and not stumble across any issues I haven’t accounted for / unknown unknowns / circumstances don’t change, it will take me about 2 weeks” followed by “in my experience, most of the time issues do come up, therefore a more conservative estimate is on the order of magnitude of months, not weeks.” This way I can calibrate with others who are estimating “how long does this take if everything goes completely smoothly” while also bringing up how unrealistic this is.
I often use the following way of explaining time estimates. “If I was to do thing X and not stumble across any issues I haven’t accounted for / unknown unknowns / circumstances don’t change, it will take me about 2 weeks” followed by “in my experience, most of the time issues do come up, therefore a more conservative estimate is on the order of magnitude of months, not weeks.” This way I can calibrate with others who are estimating “how long does this take if everything goes completely smoothly” while also bringing up how unrealistic this is.