What kind of photos are you looking for? Are you looking for formal portraits, casual photos, or something in between? Studio photos are typically more formal, while outdoor photos can be more casual or even adventurous.
What time of year is it? If you're getting your photos done during the winter, you may want to consider a studio shoot if you don’t like the cold. If you're getting your photos done during the summer, you may want to consider an outdoor shoot, as the natural light can be very flattering.
What kind of mood are you trying to create? Studio photos can create a more formal and controlled mood, while outdoor photos can create a more relaxed and natural mood.