There is wisdom in not changing routines constantly and rashly. The wisdom is financial, practical, and artistic.
On the other side of the coin, you need to change routines over time. You don’t want to fall into a rut. You have to reinvent yourself. You must also maintain your show’s dynamism, or it will become stale and outdated.
On top of these reasons, I change routines to get myself from being bored. Doing the same act over and over again bores me.