As an engineer, I can have a hard time with this very important product management technique. We’re driven to seek elegant, flexible solutions, test thoroughly, take time to refactor, and leave a code base better than we found it. But sometimes our perfectionism can keep features from making their way out the door.
Truthfully, timeboxing can be your best friend if you let it. The time limits forces you to ignore distractions and prioritize work. It keeps those perfectionist tendencies in check, and limits the amount of time spent on low-value activities.
The constraint ensures that the team is building and delivering the most valuable work as soon as possible and those less critical tasks are left to the end. Sure it may mean that some requirements won’t get implemented but what gets shipped are the most vital requirements.
I found The Ultimate Agile Planning Handbook to be a good read on the subject. Check it out.