Never settle for cosmetic changes when what's needed are critical changes.

And don't go for critical changes when all that's required are cosmetic changes.

What's the difference between the two?

Cosmetic changes are superficial, easy to make, and don't cost too much.

They are on the surface changes and don't have much impact.

Critical changes are thorough, challenging to make, and can cost a great deal.

They reach deep and have a significant impact.

Know when to make cosmetic changes and when critical changes are needed. 

And don't substitute one set for another.