Daily Surveys can be taken one or more times per day. This is indicated in the survey description. Other targeted surveys can be taken as you see them. Be sure to complete these when you see them. Some surveys may accept a limited number of responses from people matching your demographics, and can sometimes disappear quickly. New surveys come out all the time too!
Be honest. Talk about what you like and don’t like. Be fair and build trust. It will serve you well later. For examples, check out my review posts about Elite Blog Academy and Self Publishing 101. I get emails frequently from people who tell me they decided to purchase one of those courses through my affiliate link because it was the most balanced review they found.