We have seen this many times. We get bored with our ads LONG before our customers do.
When you have a paid advertising campaign that works, keep running it. Do not change it.
For a a client we checked on their sales, what was selling. Then focused campaigns on that. They doubled sales.
In the past, every month the focus changed. By staying the course they made more sales.
2 months later, they want to change it. Do you think that’s a good idea?
For any campaign you need to have a good structure. This means, if you want to test something, your structure allows you to be able to do it.
For instance, you split your budget 80/20.
80% is always on what is working. You do not touch it.
The 20% is where you test something new or different.
And ONLY when this performs substantially better, do you implement it wider.