The tile contractors “that have been laying tile for years”, that come in with their customer. Soon as their client goes to the restroom, they pull me aside and ask me:

“How much tile do I need (and proceeds to give me the dimensions in inches)?

“Is this porcelain or ceramic?”

“What kind of grout should I use?”

“Can I install this [18×18] in the customer’s shower floor(!) ?

“Do you have any more of this grout, I need like, oh, I don’t know, a couple dozen (points to the tubes of caulk)?