Product and sales always want exact dates from tech but always seem to be a lot more vague when it comes to customer numbers and revenue numbers. I've found th

Product and sales always want exact dates from tech but always seem to be a lot more vague when it comes to customer numbers and revenue numbers. I've found the following system to work well. Estimates are always given as the following: hours, days, weeks, months, quarters. That's it, not numbers attached. It means "some small number of _______". This allows for discussion without everyone feeling trapped. If a feature takes "weeks" and Product thinks it should take "hours", then that is a discussion that can allow for a change in scope or requirement clarification or just education about how the system works. Of course, PjM systems only work if everyone buys in and that is always the bigger challenge.