I am using a bathroom designer. She does not only do bathrooms, but also kitchens. I would imagine that many people do not use them because they are cost prohibitive. Mine charges $90 an hour.

Ditto on it being cost-prohibitive. Many designers are also utterly clueless about normal people's budgets, which drives people away from using designers at all. I spoke to two kitchen/bath designers when I was beginning to plan my master bath project. Neither one was willing to even touch my project since I wasn't going to be spending a minimum of $25,000. In fact, one of them LAUGHED quite patronizingly when I told her my budget (about half of her "minimum")! I had no choice but to figure it out myself, with help from Bill and a bunch of folks here, and luckily I found an inner eye I didn't know I had.

Bathrooms are mostly labor, plumbing, tile etc. Material costs are a much lower % than in a kitchen. $90 an hour for design work that conforms to codes, health safety issues is cheap. Do you shop price when you need a doctor? Thats why if your not doing a complete bath its not worth the time involved unless you pay a design fee. If your only doing a remove and replace what's there, then you may not need the knowledge a bath designer can offer, and shouldn't pay for it.

Funny, I would never think of NOT using a designer. But that has a lot to do with our particular circumstances.

While my husband and I are quite handy (he used to be a project manager for a home builder, and held many construction jobs in his college and post-grad days), what we lack is TIME -- and being a DIY-er requires lots of that. Hence, we have found reliable contractors to handle a lot of tasks in our lives, leaving what little precious time we have beyond our time-devouring careers to things we consider more important.

My bath designer is also a kitchen designer (I didn't hire him to do my kitchen because he exceeded my budget by 100%). His bath design has helped optimize the use of our decent-sized but not overly-generous master bath, and will have all the features we want without doing too much violence to the already-existing plumbing and working around a large but inconveniently placed window. More importantly, his company will also serve as our general contractor, so it's basically one-stop shopping for us. While I know we'd save some money by doing it ourselves, we save time and headaches -- a trade-off we're willing to make.

[Of course, the jury is out on all of this! We have our contract and our design, but work hasn't started yet. We'll be getting our schedule today.]