Don’t promise dates for new features

I've seen so many people I respect give this warning that it's worth its own little post: don't ever promise dates for new features. Today, I was reading the co-founder of Freckle (an indie time tracking app) discuss some things they learned over the years, and one was to not promise dates for features.

I've also seen Pippin Williamson, Brad Touesnard, and many other people give this advice.

Thomas states it like this:

Just don’t promise launch dates for a feature. Ever. No seriously, trust me on this. People will ask you all the time when β€œfeature X” is ready. A good way to answer that question is (if you plan on doing it), β€œWe’re considering this feature for a future version. I can’t give you a date on when it will be ready.

Just be honest to your customersβ€Šβ€”β€Šyou don’t know yourself if and when a feature will really be ready.

Even in my own experience running a website, I've made promises that then have been hard to keep. I need this advice, and maybe you do too.