In the case of primer, you should use only a very small amount and spread it very thinly on areas where pores are prominent or oil tends to build up, such as the nose, chin, and cheeks!
For those who find it difficult to control the amount and experience makeup smudging or caking when applying only primer, a good method is to blend the product by patting the applied area with a makeup puff after spreading the primer.
Also, if you use an eye makeup primer on your eyelids and under-eye line, it improves the color payoff of your eyeshadow and helps extend its longevity.
As for setting sprays, most of you probably use them by spraying them on after you've finished applying makeup, right?
Of course, that is a really good method, but it is also good to use a setting spray while applying makeup.
When applying base, soaking the sponge or puff with a setting spray will further increase longevity and
There is also less risk of the base peeling off.