Kitten sneezing. When should I worry?

My 3 month old kitten is sneezing. Not regularly, but every day. Once when I picked her up and held her close to my shirt. Once when she was playing on the floor. Every day she sneezes. Not all day, but on occasion. She was at the vet for a checkup just this past Saturday and all was fine (this was before the sneezing started). Do I need to bring her back to the vet?