Genetic screening ... thoughts?

I am trying to determine if I would like to do genetic screenings. I am adopted and know nothing about my family history. For that reason, I am strongly considering genetic screening tests.

At the same time, I know these can be costly and I do not want to throw money at something that may not be nessecary.

Has anyone else done these? Do you feel it was worth it? Did you have better peace of mind after?