I really enjoyed this post from Dave Rupert.
I like what Dave said:
Demos improve meetings. I’ve found “Demo First” meetings are life-giving because they start with something tangible, as opposed to discussing some hypothetical future scenario until time runs out and you have to schedule more meetings. Start meetings by showing progress. Better yet, a demo doesn’t always need to be a call or a meeting; thirty second screencasts are as good as gold.
When I'm working with our designer, I love to make quick little screen recordings and send them their way to make sure I'm on the right track. It's a good way to get out of the "hypothetical" realm.
But, not all my tasks work so closely with our designer. I need to be better at demoing what I'm working on as I go instead of putting my head down for a week or 2 and throwing it over to QA, hoping it's okay. Demos are great. They always spark conversation and ideas.