"Really? X will take 'a month at least'? Why?" "I don't know why, but I don't feel comfortable guessing less because I don't fully understand X." "Okay, that

"Really? X will take 'a month at least'? Why?" "I don't know why, but I don't feel comfortable guessing less because I don't fully understand X." "Okay, that's not a good way to estimate. Why don't you spend some time to come up with a plan for X and we can estimate it after that. When can I have the plan?"