The biggest problem I've seen isn't the estimate itself but the telephone game that happens after. You say "probably 2-3 weeks" to your manager, who tells the PM "about 2 weeks", who tells sales "mid-month", who tells the customer "the 15th".
By the time it reaches the customer, your rough guess with explicit uncertainty has become a hard commitment with legal implications. And when you miss it, the blame flows backward.
What's worked for me: always giving estimates in writing with explicit confidence levels, and insisting that any external date includes at least a week of buffer that I don't know about. That way when the inevitable scope creep or surprise dependency shows up, there's room to absorb it without the fire drill.
By the time it reaches the customer, your rough guess with explicit uncertainty has become a hard commitment with legal implications. And when you miss it, the blame flows backward.
What's worked for me: always giving estimates in writing with explicit confidence levels, and insisting that any external date includes at least a week of buffer that I don't know about. That way when the inevitable scope creep or surprise dependency shows up, there's room to absorb it without the fire drill.