If you get a talented one it can be well worth it. What they do when they do it right is to light your home and all of your stuff in a way that makes the home look better at night than it can during the day. They help you select and place fixtures that are appropriate based on both science and art. One doesn't need any special training to call themselves a lighting designer and not all good designers have formal training so it's hard to figure out who is going to do a good job. You need referrals and interviews. There are going to be differing views. Some designers have learned not to trust new stuff and others embrace the latest technology. There are tips on hiring a designer on the websites for professional designers.

Here is a link that might be useful: IALD

dim4fun thanks for the reply and the link. Do you or anyone else have an idea what a lighting designer fee usually is? I'm sure it is based on square feet. Also I'm a little worried I may end up spending alot more money on fixtures than I otherwise would.

The fee depends on how much help you want and how independent you want the designer to be. Free designs are available from places that design lighting they will sell to you. This can be a problem because what they have to sell may not be best for you. There may be a better choice in a brand that they don't carry. Going up from free you usually get more service at increasing costs. Drawing in pencil on your plans is usually fairly inexpensive. Developing a fully detailed CAD drawing with fixture legend is more expensive. Site visits during the build with revisions to the plans is more again. The fixtures may not cost more each but you will likely buy more fixtures of different types than a typical spec home plan would call for. Read the info on what a designer does. You can develop a budget to work within.

I second much of what dim4fun says.

Lighting designers (LDs) can bring in new ideas, and can really help you see the whole picture. References are very important. Also, make sure you work with one that understands YOUR goals. I know many LDs. Most are wonderful. What part of the country are you in?

I am located in Northern Utah. I was quoted $1/sq ft, but my biggest concern is how much the lighting they want me to buy will be.