Have you got error messages when using applications that have made you wonder whether a real person wrote these messages? It has happened to me numerous times. The best error message I have ever seen is when Pro/PDM, a CAD data management product from PTC once crashed with the error message – “Gastronomic error occurred, exiting” – I am not making this up – this was in 1996.
Though software development has made great strides since then, the usefulness of error messages have not changed that much. I was visiting one of the websites today (I cannot reveal the site name), when this information message caught my attention.
I was quite happy to notice that they wanted to improve my shopping experience, but look at the message. I am left to figure out when the site would be down. What would it have taken to say the exact date and time when the site would be down – nothing. But I speculate that some web developer discovered a cute little function that could update the number of hours and minutes to shutdown real time and he/she would have said”Wow, cool”. If the person who put this message together had stopped to think for one second whether the message provided the useful information he/she wanted to convey (the information that his/her customers could process), he/she very likely would have changed the message.
Think about all the information you put out there for your users and think about how much of it would make sense to them. Your users don’t have your product as the center of their universe, they are using it as a tool to get their real job done. Do all the messages that your product puts out help them get their job done? – that is the only benchmark that matters.
It is up to us as Product Managers to emphasize to our documentation/development teams that error/informational messages put out by the product has a significant enough influence on usability and user perception of your product that enough attention should be put in writing user friendly messages (and not one that makes great sense to developers alone).
Software Product Manager by Gopal Shenoy 
Maintenance windows should be scheduled on a regular basis. All updates should be made during those windows. The windows should be communicated in advance, so users can plan around them.