What are the best practices for using Value Rules in Meta Ads?

[Jack811]

I'm currently using Value Rules to reduce wasted ad spend across different age groups.
I've noticed that only one specific age group consistently generates purchases at a good CPA, while the others spend budget without delivering meaningful results.

Once a campaign reaches around 10 purchases, I'm considering two approaches:

1. Aggressive adjustment: Decrease bids by 80% for underperforming age groups while increasing bids by 20–30% for the best-performing group.
2. Gradual adjustment: Decrease bids by 20–30% for underperforming age groups while increasing bids by 20–30% for the best-performing group.

Which approach would you recommend?

Also, is it generally more effective to increase bids for high-performing age groups or placements, or to decrease bids for underperforming ones?
I'm curious whether rewarding what's working is a better strategy than penalizing what's not, particularly when it comes to maintaining stable delivery and improving overall CPA.

 

[davamosk]

I'm more a fan of decreasing low‑performing ones than boosting the good ones, but I lack a fixed system because my value rules focus on placements rather than age groups. Combining both has never worked for me because I end up paying too much in CPM due to excessive filtering.