Photography is not just about the Gear, it is what you do with it. Having said that, having appropriate gear, more importantly choosing appropriately from what you have will have a big impact on the quality of images you create and also the mood of the pictures. But it is also very important not to waste better part of the day just changing gear and equipment.
I carry just one camera body and 3 lenses. Based on the mood of the day I will choose 1 lens for the full shoot. Very rarely do I switch to another, when I do, it has to have an absolute reason.
This picture of Lachu is on a 50mm Lens, shot from a good distance to get all of her in the frame. The camera is on the ground, and the front bokeh is the grass on the ground.
So what I mean to say is that general rules need not always apply. There is a general thought that 50mm, 85mm are for tight headshots and mid-shots. Also most photographers use 70-200mm too for full lengths in a studio.
As a rule, I buy prime lenses only (24, 50, 85mm). I feel the zoom lens restrict my creativity by making me sit back and frame my shots from a fixed position. Where as a prime always keeps you on your toes, and thus also make you try new frames. Also, the distortion on a prime lens is much much less than on zooms. Sharpness of-course, there is nothing that can beat a prime.
This shoot, we shot completely on a 24mm through out the day and night. But for this set, I changed to a 50mm, just to get up-close and turn the mood upside down.
So yes, choose your gear carefully, and use them even more carefully. Don't be caught up with trying too many things. Having a basic solid gear set should be your best investment for a long time. The longer you spend time with your same gear, better will be your mastery over it.