I love tile. I go to the tile store and I am like a kid in the candy shop. I told this to my friend and she looked at me like I was crazy. She would describe her experience as anxiety filled and overwhelming. I understand why she would feel that way, and why other clients I have worked with feel that way too. That's why I liken the design process to assembling a puzzle. A good designer is going to help you get a clear picture so that you can reference it as you are putting the pieces together. Not using a professional to help you navigate the process, and you have all these pieces but no clear direction.
Anyway, I digress. My thought was this. The basement bathroom tile was the least important. The master bath was the most important. What I came up with was the following; wood plank style tile in the basement with simple subway tile. Subway tile backsplash in the kitchen. First floor bathroom I wanted to contrast dark and light with brass accents, so I went with an elongated subway tile and white hex floor with dark gray grout. The kids bath was to be fun, so I went with gray floor tile 12x24's (always go dark on floors with boys) and a textured white 12x24 and confetti accent niche. The master bath is my white and gray oasis. Marble floors, arabesque detail in niche and glossy white tile on the shower walls. The steal I found was on the mudroom floor. I wasn't looking for anything special but I found this gray tile with movement that is going to work great with muddy boots coming into my house.
Another reason a designer is important is for determining edging. I can't tell you how many times I see a production house or a flip and you can tell they just picked tile off the shelf at home depot and didn't think about transitions. Exposed raw edges are ugly, too large of grout lines look cheap, white isn't the only grout color nor is it always the best choice (remember what I said about boys bathrooms) and is Schluter or bullnose your best option. Oh yes, and quantity. Direction and inlay is going to effect your numbers, which effects your budget. Order to few and you push your timeline back, order too many and it is money down the drain.
I could go on, but I'll spare you. I'll let these pictures of the job in process do the talking for me.