Don't go live on a Friday

Unless you have mastered continuous integration, and are delivering little and often, don’t go live with big changes on a Friday.

When pushing big changes out there are two ways things can go wrong: catastrophically, or in some significantly nuanced way, that it takes a while to notice.

If something doesn’t go to plan, you will either struggle with it all day, or you will notice a few hours later. Either way, on a Friday, your technical and support people will likely be depleted and thinking of the weekend, or have already disappeared when you need them.

Deploy big things on a Tuesday or Wednesday.