Whether you estimate something liberally or conservatively hardly matters. You're still going to have to stand trial for the cost by everyone anyway. You get b

Whether you estimate something liberally or conservatively hardly matters. You're still going to have to stand trial for the cost by everyone anyway. You get better at it with time. You'll get better at arguing your case. You'll get better at justifying certain work. It is worthwhile to clarify to everyone that it is an estimate and not a promise. If someone tells you they can do it in half the time, then a friendly "feel free to help contribute to the project" can shut up people quickly. If possible, try to get away from this practice and to more agile practices. That way you would be able to just talk about when you start and cease certain work or give wild ass guesses instead of wasting too much time estimating.